Supermarket price traps: the tricks that make you pay more

Updated regularly. Supermarkets are designed to make you spend more than you intended, with legal, well-studied tricks. Knowing the four most common price traps lets you see through them and pay only the real price. The best counter to all four is the same: the price per kilo or litre, compared across several chains.

Rappn is the only neutral grocery price comparison app in Switzerland, with no commercial agreement with any retailer. Migros, Coop, Aldi, Lidl, Denner, Aligro and Otto's do not pay us to rank them, and nothing below is sponsored.

What are the most common supermarket price traps?

1. Crossed-out reference prices. A crossed-out price is no proof of a bargain. Since the Federal Council amended the Price Indication Ordinance on 30 October 2024, a comparison price may be used with no time limit only if the good was previously offered at that higher price for at least 30 consecutive days. 2. Volume deals that are not. "X for Y" or bulk packs are not automatically cheaper; what counts is the unit price per kilo or litre, which by ordinance (PBV Art. 3) must be displayed. SECO gives the example of jam at 185 grams for CHF 2.70, which works out to CHF 14.95 per kilo. 3. Shrinkflation. Same price, less content. Reported cases: Kiri shrank from 160 to 144 grams at the same price, a Snickers bar from 50 to 44 grams, a Coca-Cola bottle from 500 to 450 millilitres (later partly reversed). 4. Shelf placement and charm prices. High-margin goods sit at eye and grab height, cheaper alternatives up top or down low. And prices deliberately end in .95 or .90 to look lower.

Why a neutral comparison is the best defence

All four traps aim to make you look at a single price in the store, the crossed-out one, the pack price, the .95 price. The Foundation for Consumer Protection even runs a reporting platform for shrinkflation, because hidden downsizing is so hard to spot. The only reliable counter-value is the real price per quantity, compared across several sellers. That is exactly what the Rappn app provides: you enter a product and see the current price across every chain, instead of relying on the staging on the shelf.

Why the price traps work on us psychologically

The four tricks do not work because you are careless. They work because they lean on deeply wired habits of thought, and once you can name the pull, you start to catch it in yourself on the next aisle.

The first lever is price anchoring. A high crossed-out number plants a reference value in your head, the current price is judged against it, and it feels like a deal even when it is not. That is exactly why the 30-day rule matters: it is meant to stop an anchor price that was never really charged from skewing your judgement. The second is the left-digit effect. A price ending in .95 is read mostly by its first digit, so it feels noticeably cheaper than it is. The third is quantity framing: wording an offer as "X for Y" pushes your attention onto the saving per unit and away from the real question, whether you need that quantity at all. The fourth is plain inattention. We remember the price, not the weight, so shrinkflation slips past unnoticed because the number on the label does not move.

All four aim at the same weak spot: your eye resting on a single, staged number. The one reliable defence stays the same sober comparison, the real price per kilo or litre, set side by side across several chains.

Let Rappn compare the real price per kilo for you, and crossed-out numbers and .95 endings lose their power. How to deliberately avoid impulse buys is in avoid impulse buys, and the biggest saving levers are collected in how to save on groceries.