# Strike-Through Prices in Online Stores: What the 30-Day Rule Allows in 2026 Source: https://wernerstrauch.com/en/blog/strikethrough-prices-price-indication Language: en Author: Werner Strauch Published: 2026-11-09 > Strike-through prices, percentage discounts and RRP comparisons under the EU Price Indication Directive and the German PAngV: the 30-day rule explained, court rulings up to 2026, Shopify and Shopware, Google Shopping, Amazon, Austria and Switzerland. With a calculator. Black Friday is around the corner, and crossed-out prices are everywhere. Many of them are wrong. In a check by the European Commission and national authorities of Black Friday week 2025, almost one in three of 314 online retailers displayed discounts incorrectly. The reference price was not the lowest price of the last 30 days, as the law requires. For online stores, this is not a side issue. In Germany, a wrong strike-through price quickly leads to a cease-and-desist letter costing four figures. And it is hard to avoid with good intentions alone if the store does not even know its prices from the last 30 days. Most guides come from law firms and explain the law. This article also explains how to plan promotions and implement the rule in Shopify, Shopware, Google Shopping and on marketplaces. * * * ## The short answer **What applies to strike-through prices?** Anyone advertising a price reduction to consumers must state the lowest total price they charged in the 30 days before the reduction. This comes from Article 6a of the EU Price Indication Directive, introduced by the Omnibus Directive, and in Germany from Section 11(1) of the Price Indication Ordinance (PAngV). It applies to crossed-out prices, “instead of” prices and percentage discounts. **What is the discount based on?** On that lowest price of the last 30 days, not on the regular price. The Court of Justice of the European Union ruled this in 2024 (C-330/23). Since October 2025, the German Federal Court of Justice also requires this price to be shown “unambiguously, clearly recognisable and easily legible” (I ZR 183/24). A footnote is not enough. **And the RRP?** A comparison with the manufacturer’s recommended retail price does not fall under the 30-day rule by law. But if it looks like a discount, for example with a percentage, some German courts still treat it as a price reduction. Until the Federal Court of Justice decides, the safe route is: show the RRP neutrally, without a percentage. * * * ## What is a strike-through price? A strike-through price is a crossed-out price next to the current price. It signals that the product has become cheaper. Consumers usually understand it as the **retailer’s own former price**. That is why the rules on price reductions apply. Four forms of price advertising matter legally: - **Strike-through or “instead of” price:** “~€49.99~ €37.99” or “€37.99 instead of €49.99” - **Discount in percent or euros:** “-24%”, “You save €12” - **RRP comparison:** “RRP €59.99” next to your own price - **Comparison with other retailers’ prices:** “Elsewhere €54.99” A **fictitious reference price** that was never seriously charged has always been prohibited as misleading advertising under unfair competition law. The 30-day rule now makes this trick verifiable. * * * ## The 30-day rule explained In Germany, the rule has applied since 28 May 2022. Section 11 PAngV has four parts: 1. **Obligation:** Every announcement of a price reduction must state the lowest total price of the last 30 days before the reduction. 2. **Progressive reduction:** If the price is lowered further during a promotion without interruption, the lowest price before the promotion started may be shown for the whole promotion. 3. **Unit price:** The rule also applies to sellers who only have to state a unit price. 4. **Exceptions:** individual price reductions, and perishable goods reduced because they are about to expire, if this is made clear to consumers. ### A worked example A store normally sells a jacket for €49.99. Three weeks ago, it ran a promotion at €44.99. Now the jacket is going into the Black Friday sale at €37.99. - **Wrong:** “~€49.99~ €37.99 (-24%)”. The strike-through price is above the lowest price of the last 30 days. - **Right:** “~€44.99~ €37.99 (-15%). Lowest price in the last 30 days: €44.99.” The advertising becomes more honest and the discount smaller. That is exactly why it pays to plan promotions instead of starting them on short notice. * * * ## Which rule applies to your advertising? Not every discount claim falls under the 30-day rule. Whatever does not must still be true and clear, otherwise it is misleading under unfair competition law. The overview below is based on the German ordinance, the European Commission’s guidance on the Price Indication Directive and German case law up to November 2026. | Type of advertising | State the 30-day price? | What to watch | | --- | --- | --- | | Strike-through or „instead of“ price with your own former price | yes | strike-through price = lowest price of the last 30 days, clearly visible | | Discount in percent or euros („-20%“, „you save 33%“) | yes | calculate the percentage on the 30-day price, not the regular price | | Discount code for everyone („20% today with code XY“) | yes | counts as a general price reduction | | Personal voucher, loyalty points, customer account discount | no | individual reduction, exception under Section 11(4) | | App or loyalty card price | unclear | always show the price without the app too (Heilbronn Regional Court, Lidl Plus) | | Comparison with RRP | disputed | no percentage or discount styling, add the 30-day price | | Comparison with other retailers' prices | no | must not mislead, source and date clear | | Introductory price | no | the introductory price later becomes the former price itself | | „3 for 2“, bundle, set | mostly no | a strike-through price on a set looks like a reduction (BGH, order of 02.07.2026) | | „Up to -50%“ | yes, per item | enough items must actually get the maximum discount | | Progressive reduction in a sale | yes | the price before the sale may stay as reference (Section 11(2)) | | Perishable goods close to expiry | no | state the reason for the reduction, a best-before date alone is not enough | [Als Excel herunterladen](https://wernerstrauch.com/downloads/tables/strikethrough-prices-rule-matrix-en.xlsx) Two points are often overlooked in practice: - **Raising the price before a promotion does not help.** If you increase the price shortly before the sale, you still have to use the lower price of the last 30 days as reference. - **The 30-day price applies per channel.** According to the EU guidance, the price at the respective point of sale counts. A cheaper price in your physical store does not change the reference price in your online store. Austria even writes this into its law. More in the article on [unified commerce](https://wernerstrauch.com/en/blog/unified-commerce). * * * ## Strike-through RRP: the 2026 dispute German courts disagree on the RRP. The law speaks of reducing your own price, and an RRP is not your own price. But the EU guidance also says that if a comparison looks like a price reduction to consumers, the rule may still apply. According to the Federal Court of Justice, the overall impression of the advertising decides. **Against the 30-day obligation for RRP comparisons:** - Stuttgart Higher Regional Court, 06.03.2025, 2 U 142/23: a reference to an RRP is generally not a price reduction. An appeal is pending at the Federal Court of Justice. - Ingolstadt Regional Court, 30.09.2025, 1 HK O 1943/24: a crossed-out RRP with a percentage is not automatically a price reduction. - Cologne Higher Regional Court, 15.05.2026, 6 U 92/25: an explicit reference to the RRP explains the comparison sufficiently. **For the 30-day obligation for RRP comparisons:** - Düsseldorf Higher Regional Court, 18.12.2025, I-20 U 43/25: Aldi Süd advertised “RRP 1.29” and “-23%”. Because the design looks like a discount, Section 11 PAngV applies. - Munich Regional Court I, 14.07.2025, 4 HK O 13950/24: Amazon was not allowed to calculate Prime Deal Days discounts on the RRP instead of its own former price. The case is on appeal. - Düsseldorf Regional Court, 17.07.2026, 38 O 219/25: with “55% SAVE NOW”, the reference to the RRP was too unclear. ### How to advertise until the Federal Court of Justice decides Until then, your risk depends on which court is responsible. That is why the cautious route is also the commercially sensible one: - label the RRP clearly as the “manufacturer’s RRP”, not just “RRP” in small print - no percentage, no “you save” and no discount styling next to the RRP - also state your own lowest price of the last 30 days - only show an RRP if it is current and actually published by the manufacturer * * * ## The most important rulings from 2024 to 2026 | Date | Court, case number | Key point | | --- | --- | --- | | 26.09.2024 | CJEU, C-330/23 (Aldi Süd) | discount must refer to the lowest price of the last 30 days | | 06.03.2025 | Stuttgart Higher Regional Court, 2 U 142/23 | RRP reference generally not a price reduction, appeal at the BGH | | 18.03.2025 | Heilbronn Regional Court, 21 O 105/24 KfH | app price (Lidl Plus) without the regular price challenged | | 14.07.2025 | Munich Regional Court I, 4 HK O 13950/24 | Amazon Prime Deal Days: discount on RRP instead of own former price not allowed | | 05.08.2025 | Nuremberg Higher Regional Court, 3 U 2376/24 | perishable goods: reason for the reduction must be clear, best-before date not enough | | 30.09.2025 | Ingolstadt Regional Court, 1 HK O 1943/24 | crossed-out RRP with percentage not automatically a reduction | | 09.10.2025 | Federal Court of Justice (BGH), I ZR 183/24 | 30-day price must be unambiguous, clearly recognisable and easily legible, a footnote is not enough | | 18.12.2025 | Düsseldorf Higher Regional Court, I-20 U 43/25 | RRP with „-23%“ is a price reduction, Section 11 applies | | 13.02.2026 | Cologne Higher Regional Court, 6 UKl 4/25 | price advantage must refer to the 30-day price, additional prices must be explained clearly | | 03.03.2026 | Karlsruhe Higher Regional Court, 14 U 83/25 | „you save 33%“ falls under Section 11 PAngV | | 27.03.2026 | Cologne Higher Regional Court, 6 U 77/25 | qualifying the discount only on the next page in small print is not enough | | 15.05.2026 | Cologne Higher Regional Court, 6 U 92/25 | explicit RRP reference is not a price reduction | | 02.07.2026 | Federal Court of Justice (BGH), I ZR 242/25 (order) | overall impression decides, strike-through price on a set suggests a reduction | | 17.07.2026 | Düsseldorf Regional Court, 38 O 219/25 | „55% SAVE NOW“ with unclear RRP reference not allowed | [Als Excel herunterladen](https://wernerstrauch.com/downloads/tables/strikethrough-prices-rulings-en.xlsx) For online stores, the Cologne case 6 U 77/25 is especially relevant. A large discount on the category page that is only qualified in small print on the product page is not enough. The 30-day price must appear wherever the discount is advertised: in the listing, on the product page, in the banner and in the newsletter. * * * ## Calculator: permitted reference price and correct discount Enter the regular price, the lowest price of the last 30 days and the planned sale price. The calculator shows which reference price you may use, the correct discount and when the regular price works as a reference again. 30-day price check Guidance under the EU Price Indication Directive, not legal advice Result – Permitted reference price – Correct discount – Discount on the regular price (not permitted) – Regular price usable as reference from – Your price line could read – [Have your store's pricing logic reviewed →](https://wernerstrauch.com/en/contact) Your inputs and the result are copied into the contact form. Simplified check for one promotion in one channel. Not legal advice. As of November 2026. * * * ## Implementing strike-through prices in Shopify, Shopware and WooCommerce The problem is rarely a lack of good intentions. It is the technology. **None of the major store systems reliably calculates the lowest price of the last 30 days on its own.** The store only shows what is in the field. Who maintains the field and where the price history comes from is up to the retailer. | | Shopify | Shopware 6 | WooCommerce | | --- | --- | --- | --- | | Field for strike-through price | compare-at price | list price | regular price with sale price | | Field for 30-day price | no, only via metafield and theme | yes, „cheapest price (last 30 days)“ since 6.4.10 | no, only via extension | | Calculated automatically | no | no, manually, via bulk edit or API | no | | Typical solution | app, for example Omnibus apps that store a price history | plugin or price feed from ERP or PIM | extension, for example Latest Lowest Price | | Pitfall | compare-at price is display logic, not legal logic | value goes stale if nobody updates it | prices from plugins and roles often not captured | [Als Excel herunterladen](https://wernerstrauch.com/downloads/tables/strikethrough-prices-store-systems-en.xlsx) ### Shopify Shopify recommends entering the lowest price of the last 30 days in the **compare-at price** field and the sale price in the **price** field. That works as long as promotions are rare and someone knows the prices. For frequent discounts, Shopify itself recommends adapting the theme so that the regular price and the lowest prior price are shown separately. The 30-day price then comes from a metafield. Three points make it tricky in Shopify: - **Variants:** The 30-day price applies per variant. A jacket in size M can have a different price history than in size L. - **Markets:** Every market with its own prices has its own history. For merchants whose primary market is outside the EEA, Shopify’s help center says compare-at prices are hidden for EEA markets by default. - **Discount codes and automatic discounts:** They change the price in the cart, not in the field. A general promotion with a code is still a price reduction. ### Shopware 6 Since version 6.4.10 (April 2022), Shopware has had dedicated fields for the cheapest price of the last 30 days, gross and net. The value appears in the listing, on the product page and in the cart. But Shopware deliberately does not calculate it. The vendor’s reasoning: rules, promotions and vouchers make automatic detection too complex. You supply the value via bulk edit, via API from your ERP or PIM, or through a plugin. The most common gap: the field was filled once at launch and never updated again. Then the store shows a 30-day price that is wrong. That is worse than showing none. ### WooCommerce WooCommerce knows a regular price and a sale price, but no price history. For the 30-day price you need an extension. Check whether it also captures prices set by other plugins, such as role-based or dynamic prices. ### Who owns the price? ERP, PIM or store In many stores, prices are created in the ERP, enriched in the PIM and overwritten in the store by an app. Then nobody knows which price applied when. Three rules help: 1. **One system is the master for prices.** Usually the ERP or a pricing tool. All others take over its prices. 2. **The price history is stored** per product, variant, channel and market, with a date. In a dispute, it is your evidence. 3. **One person approves promotions.** Marketing plans, pricing checks the 30-day price, IT makes sure the store and feed show it. * * * ## Google Shopping, Amazon and price comparison sites Discounts are not only advertised in the store. Via the product feed, the strike-through price ends up in Google Shopping and on price comparison sites. Their platform rules apply on top. ### Google Merchant Center Google only shows a crossed-out price in Shopping ads if you submit a sale price (`sale_price`) and these conditions are met: - The discount is more than 5% and less than 90%. - In Germany, the base price must have applied on 30 days within the last 200 days. The days do not have to be consecutive. - The original and sale price are also shown on the landing page. This creates a trap. **Google’s rule is not the legal rule.** Google accepts a base price that applied at some point in the last 200 days. The law requires the lowest price of the last 30 days. If you send the regular price as the base price in your feed, you may get a Google annotation that does not hold up legally. So pass the same reference price in the feed that your store shows. How to set up the feed properly is covered in the article on the [Google Merchant Center feed](https://wernerstrauch.com/en/blog/google-merchant-center-feed). ### Amazon and other marketplaces On a marketplace, the seller is responsible for the price information, not the operator, as long as the operator only acts as an intermediary. On many offers in Germany, Amazon shows the lowest price of the last 30 days itself. For its own RRP-based promotions, Munich Regional Court I stopped Amazon in 2025. For marketplace sellers: check which reference prices the marketplace displays from your data, and do not submit an RRP that is out of date. * * * ## Planning promotions: Black Friday, sales and introductory prices The 30-day rule is also a planning issue. If you know it, you can use it. - **30 days of price stability before major promotions.** If you discount in October, you lose the regular price as a reference in November. Put Black Friday, Christmas and the winter sale in a promotion calendar and plan the gaps. - **Use progressive reductions.** A sale that goes from 20% to 30% to 50% in stages may keep showing the price before the sale as reference. But the reduction must run without interruption. If you go back to the regular price in between, you start over. - **Label introductory prices clearly.** An introductory price is not a discount on a former price. But after the launch, it becomes the reference price itself. - **No price increase before the sale.** It does not help and is a typical reason for legal claims. - **Calculate discounts against your margin.** The discount turns out more honest and therefore smaller when it refers to the 30-day price. If you know the effect on your [gross margin](https://wernerstrauch.com/en/glossary/gm-gross-margin), you discount less often but more precisely. * * * ## Austria and Switzerland: what is different Many stores in the DACH region sell into all three countries. The rules are similar, but not the same. | | Germany | Austria | Switzerland | | --- | --- | --- | --- | | Legal basis | Section 11 PAngV | Section 9a Price Labelling Act (PrAG) | Art. 16 Price Indication Ordinance (new since 01.01.2025) | | Obligation | state the lowest price of the last 30 days | state the lowest price of the last 30 days in the same sales channel | reference price only if it was charged for at least 30 days before | | Exceptions | individual discounts, perishable goods, progressive reduction | goods offered for less than 30 days, perishable goods | introductory price and competitor comparison, type of comparison must be stated | | Sanction | fine and cease-and-desist claims under unfair competition law | administrative fine | fine up to CHF 20,000 | [Als Excel herunterladen](https://wernerstrauch.com/downloads/tables/strikethrough-prices-dach-comparison-en.xlsx) Switzerland is not an EU member and follows its own logic. You do not have to state a “lowest price of the last 30 days” there. A comparison with competitor prices is allowed if the majority of providers in the market area actually charge that price. * * * ## What happens if you get it wrong - **Cease-and-desist letter:** In Germany, a breach of Section 11 PAngV is also unfair under the Unfair Competition Act, because consumers are missing material information. Competitors, associations and the Wettbewerbszentrale can send warning letters. According to the Händlerbund’s 2026 study on warning letters, almost seven in ten retailers who received one paid a four-figure amount. - **Undertaking and penalty payments:** If you sign an undertaking or are ordered by a court and repeat the mistake, you pay a contractual penalty or a court fine. In the Amazon case, up to €250,000 per breach is at stake. - **Administrative fine:** The breach is an administrative offence under Section 20 PAngV in conjunction with the German Economic Offences Act. - **EU authorities:** The European Commission and national consumer protection authorities check discount campaigns specifically, most recently for Black Friday week 2025. The biggest risk is not the single warning letter. It is the undertaking to cease and desist. After that, every further mistake costs money, and without a clean price history, the next one happens quickly. * * * ## Do strike-through prices actually work? Yes, if they are credible. Research has shown for decades that a reference price makes an offer seem more valuable and reduces the urge to keep searching. Compeau and Grewal summarised this as early as 1998 and also called reference prices a tool with high potential for deception. Later studies confirm the anchoring effect, for example Sinha and Adhikari (2017). Specific figures like “+30% conversion from strike-through prices” usually come from app vendors’ blogs without a verifiable study. Do not rely on them. The anchor works less well the more often customers see discounts. If you discount constantly, you train customers to wait for the next sale. More on designing price information in the article on [product page optimization](https://wernerstrauch.com/en/blog/product-page-optimization). * * * ## Checklist before every promotion Checkliste 0 / 15 Punkte 0 % erfüllt Zurücksetzen Price 0/4 - The lowest price of the last 30 days is known per product, variant and channel - Strike-through price and percentage refer to this price - The price was not increased in the 30 days before the promotion - General discount codes are treated as price reductions Display 0/4 - The 30-day price is easily legible right next to the discount, not in a footnote - Listing, product page, banner and newsletter show the same information - The RRP is labelled as the „manufacturer's RRP“, without percentage or discount styling - With „up to“, enough items get the maximum discount Technology and channels 0/4 - One system is the master for prices, the price history is stored - The Google feed passes the same reference price as the store - Marketplaces do not show an outdated RRP from your data - Shopify Markets or Shopware sales channels have their own values per country Planning 0/3 - Major promotions are at least 30 days after the last price reduction - One person approves promotions - The display has been checked for Austria and Switzerland * * * ## FAQ Are strike-through prices allowed in the EU? Yes. Strike-through prices are allowed if the crossed-out price is the lowest price you charged in the 30 days before the reduction and this price is shown clearly. A price that was never seriously charged is a prohibited fictitious reference price. What is the 30-day rule for discounts? Under Article 6a of the EU Price Indication Directive and Section 11 of the German PAngV, anyone advertising a price reduction to consumers must state the lowest total price of the last 30 days before the reduction. According to the CJEU ruling of 26.09.2024, percentage discounts must refer to this price. Can I advertise with the RRP? Yes, comparing with the manufacturer’s current recommended retail price is generally allowed. Whether the 30-day rule applies is disputed in Germany: Düsseldorf Higher Regional Court says yes if the advertising looks like a discount, while the courts in Cologne and Stuttgart disagree. The safe route is a neutral RRP without a percentage plus the 30-day price. Does the 30-day rule apply to discount codes? Yes, if the code is advertised to everyone, for example „20% off everything today with code XY“. According to the EU guidance, personal vouchers, loyalty points and individual discounts are not covered. How do I show the lowest price of the last 30 days in Shopify? Shopify does not calculate it. Enter the value in the compare-at price field, or store it in a metafield and display it via the theme. For frequent promotions, use an app that stores the price history per variant. Does Shopware calculate the 30-day price automatically? No. Since version 6.4.10, Shopware has fields for the cheapest price of the last 30 days and shows it in the storefront. But you have to supply the value yourself, via bulk edit, via API from your ERP or PIM, or through a plugin. What does a warning letter for wrong strike-through prices cost? There are no figures specifically for strike-through prices. According to the Händlerbund’s 2026 study, almost seven in ten retailers who received a warning letter paid a four-figure amount. It gets more expensive if another mistake happens after signing an undertaking to cease and desist. Does the 30-day rule apply in Austria and Switzerland? In Austria, yes, under Section 9a of the Price Labelling Act, explicitly per sales channel. In Switzerland, not in this form: a reference price may only be shown there if it was charged for at least 30 days before. * * * ## Conclusion: price history first, then the discount Strike-through prices are allowed and they work if they are honest. The rule is simple: the comparison refers to the lowest price of the last 30 days, and this price is clearly visible next to the discount. In practice it gets difficult, because no store system reliably knows this price on its own, and the store, feed and marketplace often show different prices. If you store the price history properly, make one system the master for prices and plan promotions with enough distance, you advertise safely and discount less often but more precisely. With the RRP, restraint pays off until the Federal Court of Justice decides. * * * ## Sources 1. [Section 11 Price Indication Ordinance, PAngV (gesetze-im-internet.de, German)](https://www.gesetze-im-internet.de/pangv_2022/__11.html) 2. [Section 20 PAngV: administrative offences (German)](https://www.gesetze-im-internet.de/pangv_2022/__20.html) 3. [European Commission: Guidance on the Price Indication Directive (2021/C 526/02)](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52021XC1229\(06\)) 4. [CJEU, judgment of 26.09.2024, C-330/23 (press release)](https://curia.europa.eu/jcms/jcms/p1_4575171) 5. [Federal Court of Justice, judgment of 09.10.2025, I ZR 183/24 (press release 184/2025, German)](https://www.bundesgerichtshof.de/SharedDocs/Pressemitteilungen/DE/2025/2025184.html) 6. [beck-aktuell: Düsseldorf Higher Regional Court, I-20 U 43/25 (19.12.2025, German)](https://www.beck-aktuell.de/heute-im-recht/rechtsprechung/olg-duesseldorf-i20u4325-verbraucherschutz-aldi-sued-rabattwerbung-2025-12-19) 7. [IT-Recht Kanzlei: crossed-out RRP and the 30-day lowest price (German)](https://www.it-recht-kanzlei.de/durchgestrichene-uvp-30-tage-bestpreis.html) 8. [Trusted Shops: RRP comparisons in case law (03/2026, German)](https://business.trustedshops.de/blog/legal/uvp-vergleiche-rechtsprechung) 9. [Omsels: case law on price reductions under Section 11 PAngV (German)](https://www.omsels.info/die-verbote-oder-was-darf-ich-nicht/%C2%A7%C2%A7-5a-5b-uwg-informationspflichten/%C2%A7-5a-abs-1-uwg-wesentliche-informationspflichten/preisangabenverordnung-pangv/preisermaessigungen) 10. [LTO: Munich Regional Court I on Amazon Prime Deal Days, 4 HK O 13950/24 (German)](https://www.lto.de/recht/nachrichten/n/4hko1395024-lg-muenchen-i-verbraucherzentrale-gegen-amazon-prime-deal-days) 11. [Verbraucherzentrale Baden-Württemberg: Heilbronn Regional Court, 21 O 105/24 KfH (German)](https://verbraucherzentrale-bawue.de/sites/default/files/2025-04/lg-heilbronn-beschluss-vom-18.03.2025-21-o-105-24-kfh.pdf) 12. [European Commission: EU check reveals misleading sales practices online (26.03.2026)](https://commission.europa.eu/news-and-media/news/eu-check-reveals-misleading-sales-practices-online-2026-03-26_en) 13. [CCPC: 1 in 3 traders incorrectly display discounts online during Black Friday sales (26.03.2026)](https://www.ccpc.ie/news-and-media/news/article/2026/03/26/investigation-by-ec--ccpc-and-european-consumer-authorities-finds-1-in-3-traders-incorrectly-display-discounts-online-during-black-friday-sales) 14. [Händlerbund: study on warning letters 2026 (German)](https://www.haendlerbund.de/de/news/presse/pressemitteilungen/abmahnstudie2026) 15. [Shopify Help Center: Price Indication Directive](https://help.shopify.com/en/manual/compliance/legal/pricing-indication-directive) 16. [Shopware: release news April 2022 (6.4.10)](https://www.shopware.com/en/news/shopware-6-release-news-april-2022/) 17. [WooCommerce: Latest Lowest Price](https://woocommerce.com/products/latest-lowest-price/) 18. [Google Merchant Center: sale price annotations](https://support.google.com/merchants/answer/9017019?hl=en) 19. [WKO: changes to Section 9a Price Labelling Act (German)](https://www.wko.at/handel/elektro-einrichtungsfachhandel/aenderungen-in-9a-preisauszeichnungsgesetz) 20. [SME Portal Switzerland: price labelling (German)](https://www.kmu.admin.ch/de/kennzeichnung-der-preise) 21. [CMS: SECO guidance on the revised Price Indication Ordinance](https://cms.law/en/che/legal-updates/advertising-discount-pricing-in-swiss-retail-seco-provides-guidance-on-the-revised-price-indication-ordinance) 22. [Compeau & Grewal (1998): Comparative Price Advertising, Journal of Public Policy & Marketing](https://core.ac.uk/download/231826197.pdf) 23. [Sinha & Adhikari (2017): European Journal of Marketing](https://www.doi.org/10.1108/EJM-03-2016-0177)