The OCU counted 244 products across 80 categories in its 2026 comparison. In San Sebastián, the survey found a €1,676 yearly gap between the cheapest and most expensive supermarket options, more than double the €743 recorded in the previous OCU study.
Donostia's average annual basket already costs €6,751. Only Barcelona is more expensive among Spain's provincial capitals, followed by San Sebastián and Bilbao. The national average is €6,600, so a typical Donostiarra pays more before choosing a store.
Irun's average basket costs even more. The annual bill there reaches €6,880, and the gap between the city's cheapest and most expensive options is €1,696.
The OCU collected 101,520 prices across 690 establishments in 38 cities. Its figures put the possible saving in San Sebastián at €1,676, compared with €1,310 across Spain. The research appeared on 25 September 2026. El País independently confirmed the survey's scale and national conclusions. The OCU also put Spain's average annual supermarket basket at €6,602 in 2026, up 5.18% over the year.
Madrid has the widest city-level spread, at €4,381. Torrent, Villarreal and Santa Pola are the cheapest locations in the study. Getxo, Pozuelo de Alarcón, Majadahonda and Cerdanyola del Vallès are among the most expensive. ABC's coverage of the Madrid figure showed how much prices can vary between shops in one city.
Price growth has slowed from the previous two years. The OCU basket rose by an average of 1.8%. Fresh products increased 4.7%, fish 8.6%, meat 3.7% and fruit and vegetables 3.5%. Packaged goods rose 1.4%.
Brand-name products became 2% more expensive, while private-label goods rose 0.8%. Overall, 61.8% of basket items increased in price and 38.2% became cheaper. Tomatoes led the rises at 33.2%, followed by lemons at 25.2%, cauliflower at 22.8%, aubergines at 20.4% and portion-sized John Dory at 19.4%.
Some prices fell sharply. Potato purée dropped 14.8%. Artichokes fell 15.1%, Canary Islands bananas 22.6% and paper napkins 30.4%.
The longer-term picture is harsher. Since 2021, the OCU basket has risen by an average of 39.5%. Fresh products are up 44% and meat 46.8%. Economical blended ground coffee has increased 142%, medium eggs 135%, large eggs 123% and a milk chocolate bar 101%. Only laundry detergent, natural Danone yoghurt and rice drink cost less than in 2021.
Price competition between chains has also intensified. Eight of the 28 major retailers analysed cut prices. Carrefour Market led with a 2.7% reduction, followed by Lidl at 1.9%, Mercadona at 1.8% and Aldi at 1.4%. BM Urban rose 5.1% and Ahorramás 4.4%. Comparing stores matters, as earlier household data showed how quickly impressive costs can strain family budgets.
Dani remains the cheapest chain overall. Family Cash and Tifer follow, with Alcampo and Supeco also near the top. Alcampo hypermarkets are the cheapest option in many locations. Lidl now leads in 60 cities, compared with 18 a year earlier. Mercadona has doubled the number of places where it is the best-priced choice. Supeco has risen from 18 to 28.
For shoppers in Donostia and Irun, the annual bill depends heavily on where they shop. Prices are rising more slowly than before, but the €1,676 and €1,696 gaps still matter. The average basket in both cities is already above the national level. Comparing supermarkets remains one of the few immediate ways to cut a five-figure household expense over several years.
