Black Friday Discounts in Portugal Must Be Measured Against the Lowest Price of the Last 30 Days: How to Check a Deal and Where to Complain

Black Friday falls on Friday 27 November this year, and the deals have already started. Portuguese law sets a test for every one of them: the "before" price must be the lowest price the shop charged in the 30 days before the cut, not a figure the shop picks.

The 30-day rule

Price reductions are governed by Decreto-Lei n.º 70/2007. It allows three kinds of reduced-price sale: saldos (end-of-stock sales), promoções (promotions) and liquidação (closing-down or clearance sales). Decreto-Lei n.º 109-G/2021, in force since 28 May 2022, rewrote the key definitions:

• The reference price is the lowest price at which the product was sold in the 30 consecutive days before the reduction (Article 3).
• Labels and price lists must clearly show the new price and that lowest earlier price; a percentage alone is no longer enough (Article 6).
• The sale must state its type, the products covered, the lowest earlier price, and when it starts and how long it lasts (Article 4).
• If a discount grows in stages, the reference is the price before the first cut (Article 4).
• The trader must be able to prove the earlier price on paper (Article 5).
• Comparisons must use the same unit: a multipack cannot be compared with the single-item price (Article 5-A).

The rules also cover sales online and at a distance, not just shops (Article 2, as amended by Decreto-Lei n.º 10/2015). Breaking them is a "grave" economic offence. Under the 2021 schedule in Decreto-Lei n.º 9/2021, that means a fine of 650 to 1,500 euros for an individual trader and 12,000 to 24,000 euros for a large company.

Other rules during a sale

When a named product sells out, the shop must say so and end the offer. It must accept every payment method it normally takes and cannot change the price depending on how you pay (Article 7). Faulty goods sold cheaply must be labelled with the fault; if they are not, you can swap them or get your money back (Article 9). Exchanging an item that is not faulty is up to the shop. Where it agrees to an exchange, the law asks for the item in the same condition, a receipt saying exchanges are allowed, and at least five working days to do it (Article 8). Your legal guarantee on faulty goods is not affected.

Online, you can cancel most purchases within 14 days without giving a reason, under Article 10 of Decreto-Lei n.º 24/2014, as amended by Decreto-Lei n.º 109-G/2021.

What it means for you

• Watch the price now. The Direção-Geral do Consumidor (DGC, the consumer directorate) has described a real case: a coffee machine at 120 euros with a 50 euro discount that turned out to be included already, then shown at 180 euros "minus 50" in Black Friday week. A screenshot or photo taken today is your evidence.
• Check postage, returns and the seller's identity before paying online, as the DGC advises.
• Complain through the Livro de Reclamações (complaints book), which also runs online. The DGC says sudden price changes should be reported to ASAE, the economic and food safety authority, and misleading advertising to the DGC itself.

ASAE checks every November

In its December 2024 report on its Black Friday operation, ASAE said it inspected 327 traders and opened 21 offence cases, mostly for breaking reduced-price advertising rules and failing to state the type of sale or its dates. In 2022 it inspected 550 traders and opened 48 cases.

Payment rules have their limits too: as we reported, shops can currently refuse cash without a fine.