Lots of people are guilty of making this mistake – and it quickly adds up over time
Some Brits are being stung for up to £1.50 before they’ve even started the food shop – simply by turning up without a reusable bag. New research suggests the ‘small mistake’ of buying a replacement bag each time can quietly pile up, adding an average of £78 a year to household spending as bills stay tight.
The warning is aimed at anyone who shrugs off 40p here or there at the checkout. Analysis by thimbl.com found big differences in what major supermarkets charge for replacement reusable bags, with some costing almost four times more than others.
Waitrose tops the list at £1.50 for a standard bag, while many rivals charge 40p. Personal finance expert Joe Lytwyn at thimbl.com said: “Forgetting a shopping bag feels like a tiny mistake, but it’s one of those everyday costs that can quietly add up over time.
“Most people won’t think twice about spending 40p or even £1.50 when they’re already at the checkout, but if it’s happening regularly across multiple shopping trips, it becomes another unnecessary expense that’s easily avoided.” The research says the gap between supermarkets can make a real difference over time — especially for regular shoppers.
Even where the price difference is smaller (around 40p to 65p per bag at some stores), it could still add up to roughly £21 to £33.80 a year, assuming everything fits into one bag per trip.
The carrier bag tax was first introduced in October 2015 for England, meaning it has been more than a decade since people were simply handed bags at no extra cost when shopping. It started with a tiny 5p charge, which has since doubled to a minimum of 10p from 2021, but most shops can set their own prices, with some charging up to 40p per bag.
As a shopper, intentionally walking out with a carrier bag without paying for it is considered shoplifting or theft under UK law. While store staff or security may challenge you, ask you to pay, or ban you from the store, police involvement is rare for a minor item unless it is part of a larger incident or aggressive behaviour.
To avoid this often-forgotten expense, people could:
- Keep at least one reusable shopping bag in the boot of your car or by your front door.
- Store a foldable reusable bag in a handbag, backpack or work bag for unexpected shopping trips.
- Reuse Bags for Life instead of buying a new one every visit.
- Keep spare shopping bags in the places you’re most likely to need them, rather than storing them all in one cupboard.
With household budgets still under pressure, it’s worth getting into the habit of keeping a reusable bag in your car, by your front door or folded inside a handbag or backpack. It’s a small change that could save you money every time you shop.
Supermarket carrier bags ranked (from most to least expensive, as of August 2026)
- Waitrose – £1.50 per bag
- Aldi – 65p per bag
- Morrisons – 60p per bag
- Tesco – 40p per bag
- Asda – 40p per bag
- Sainsbury’s – 40p per bag
- Lidl – 40p per bag
- Marks & Spencer – 40p per bag