You’ve walked down the grocery aisle and spotted the big numbers: “50% off!” “BOGO Half Price!” “25% Extra Free!”.
But do these deals really save you money, or are they just clever marketing?
The information you need is often tucked away on hidden shelf codes, which can help shoppers uncover real bargains.
Budgeting expert Rebecca Routledge from Money Wellness, commissioned by the UK government’s Money and Pensions Service (MaPS), reveals how a few insider tricks can transform the way you shop.
Shelf Labels Aren’t Just Decoration
“Supermarket labels can tell you more than most shoppers realise,” says Rebecca.
- Loyalty-only deals often have phrases like “Clubcard Price” or “Nectar Price.”
- “Rollback” or “Price Drop” signals a temporary reduction.
- Tiny print often shows previous prices and dates, so you can tell if the deal is short-term or lasting.
Some insiders say stores even hide the end date in codes. Tesco, for example, is believed to use a reversed six-digit code (YYMMDD) - so 260121 means the offer ends 21 January 2026. Waitrose makes it simpler with four-digit dates, while Aldi flags discontinued products with a capital “D”.
Checking these codes can be the difference between a genuine bargain and a “marketing mirage.”
Master the maths for instant savings
It’s easy to get nervous when faced with percentages. Around a third of adults admit they feel anxious about maths, but learning a simple trick can turn you into a money detective.
Lyndsey Hartley, head of maths at Kelvinside Academy, recommends mastering the 10% rule:
Find 10% of any number - just move the decimal place one left.
- £10 - £1
- £55 - £5.50
Double it for 20%, halve it for 5%, or combine for other percentages.
- 25% off £8 - 10% = 80p - 20% = £1.60 and 25% = £2, so final price £6
BOGO deals? Simply calculate the total and divide by the number of items to see the true cost per unit.
Hartley also suggests the “£1 rule”: if you’re close enough within a pound, that’s accurate enough for everyday shopping — no exam stress required.
Other expert tricks
- Unit price > sticker hype: Always check cost per 100g or litre.
- Own-brand may be cheaper: Larger or branded packs aren’t always the best deal.
- Timing matters: Yellow sticker reductions often appear late in the day; aisle-end displays aren’t always cheapest.
- Multibuys only save if you need them: 3-for-£5 sounds great, but only if all three are useful.
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- Full list of DWP payments rising for parents, carers and families in 2026
Quick supermarket cheat sheet
These are the tips experts share as a guide, although individual supermarket policies may vary:
Freshness Codes
- Tesco / Asda / Morrisons: Letter = month (A-L), Number = day - D27 = 27 April
- Sainsbury’s: Starts with J, ends with S - J0811S = 8 Nov
Promotion Codes
- Tesco: Reversed YYMMDD - 260121 = 21 Jan 2026
- Waitrose: Four-digit date - 21/01 = 21 Jan
- Sainsbury’s: Start date shown; deals usually last ~2 weeks, end on Tuesday
- Aldi: Capital “D” = discontinued product
Extra Tips
- Look for yellow/red sticker reductions
- Check world foods aisles for cheaper alternatives
- Use apps like Too Good to Go for surplus food boxes
Cracking supermarket codes and learning basic percentage maths can save you hundreds per year, but the real secret is knowing your usual prices and using deals as bonuses, not triggers.
As Rebecca Routledge puts it: “A genuine bargain is something you were going to buy anyway, at a lower unit price - not just something that looks cheap.”
