What Supermarket Simulator Teaches About Reading Unit Prices

I track my grocery spending down to the receipt, which my family finds either admirable or alarming depending on the week. For two years I was sure I was a sharp shopper. Then I spent a long weekend playing Supermarket Simulator, the shop management game where you order stock, fill shelves and set every price yourself with a little label gun, and I came out of it understanding the other side of the shelf a lot better than I wanted to.

Setting prices for imaginary customers made something obvious that I had been missing in real ones: the price on the big yellow label is the one the shop wants you to read. The number that tells you whether something is cheap is the small one underneath, the unit price, and the shop has a lot of quiet ways to make it hard to compare. Once I started reading that small number properly, my weekly shop dropped by about £6.40 without changing what we eat.

What the game shows you from behind the counter

In Supermarket Simulator you buy stock by the box, see what each item costs you, and choose what to charge. The game also shows a market price, and customers grumble or walk away if you go too far above it. Very quickly you learn which levers matter. Customers notice the shelf price. They rarely think about how much is in the pack.

That last point is the real lesson. In the game, as in life, a shop makes more money from a smaller pack at a friendly-looking price than from a bigger pack at an honest one. Nobody in the game ever divided the price by the weight. Very few people in my local supermarket do either, and I did not until I had sat on the other side.

Where unit prices go wrong

In the UK, most supermarkets are required to show a unit price on the shelf edge for many foods, and in parts of the US it is required by state law or offered voluntarily. In theory this makes comparison easy. In practice, there are three habits that break it.

Mixed units on the same shelf

I have photographed shelves where one brand of tea shows a price per 100 g, the next per 80 bags, and a third "per each." Cheese is often per kg on one pack and per 100 g on the one beside it. You cannot compare £1.25 per 100 g with £11.50 per kg at a glance, even though the first is the more expensive one. UK regulators have spent the last few years pushing supermarkets to be more consistent about this, and some have improved. Many shelves still have not.

Multi-buy offers that hide the single price

A "3 for £5" sign over tins that cost £1.80 each looks like a deal, and it is, by 40p in total, if you were going to buy three anyway. But I have also seen the same sign over items that cost £1.65 when you buy one, which makes the "offer" 5p dearer than three singles. The unit price on the label usually refers to the single item, not the offer, so it will not help you decide whether the multi-buy is worth it.

Bigger is not always cheaper per kilo

We assume the big bag is the better deal. Often it is. Sometimes the shop knows we assume it, and prices the large size slightly higher per kilo than a smaller one on promotion. I have found this most often with rice, porridge oats and washing powder.

A week of my own receipts

Here is what changed when I started reading unit prices instead of shelf prices, from one ordinary week's shop in September 2026. The prices are from one supermarket and will differ where you live.

Two things in that table surprised me. The carrots went the other way: loose produce, which I had assumed was always cheaper, cost more per kilo than the bag that week. And the "offer" oats were nearly twice the per-kilo price of the plain own-brand bag on the shelf below. The offer sign was doing exactly what my pricing in the game had done: making people feel clever while paying more.

The big label tells you what the shop wants you to pay. The small label tells you what you are actually paying.

The habit, not the app

People often recommend a price comparison app for this. I tried two and stopped using both within a month, because standing in an aisle tapping in weights is slower than reading the label. What works for me is a short list of the dozen things we buy every week, with a target unit price for each written in my phone. If the shelf's unit price is under my number, I buy. If it is over, I look one shelf up and one down. That is it.

I wrote more about treating the food budget like any other budget in budgeting for groceries the way you would budget for anything else, and Marisol's guide to spotting a real grocery deal from a fake one goes deeper on offer signs. If you liked the game angle, my earlier piece on how inventory games sharpen grocery habits covers stock levels rather than prices.

Your list for this week

Take your last receipt and pick the ten items you buy most often. Next shop, photograph the shelf label for each one, including the small unit price, and write down the lowest unit price you see for that item across sizes and brands. That number becomes your target. It takes one slightly slower trip, maybe fifteen extra minutes, and every shop after that is faster and cheaper.