The supermarket mistake that could cost shoppers £1.50 before they've bought a single item

Shoppers could be paying up to £1.50 before they've even put a single item in their basket simply by forgetting to bring a reusable shopping bag, new research has revealed.

That's a habit that could sting far more than it first appears. Forgetting a bag on each weekly shop for a year could rack up as much as £78.

Analysis by thimbl has found significant differences in what the UK's biggest supermarkets charge for replacement shopping bags, with some shoppers paying almost four times as much as others for making the same simple mistake.

The research found that Waitrose charges £1.50 for its standard reusable shopping bag, making it the most expensive supermarket in the UK for customers who arrive without one.

By comparison, several of the country's biggest supermarket chains, including Tesco, Asda, Sainsbury's, Lidl and Marks & Spencer, charge 40p for their standard reusable shopping bag, while Aldi charges 65p and Morrisons charges 60p.

Supermarkets charging shoppers the most for a forgotten shopping bag

*Lowest-priced reusable shopping bag available at the checkout. Prices correct at the time of research.

Joe Lytwyn, personal finance expert at thimbl, 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.

"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."

To avoid this often-forgotten expense, Joe recommends:

• 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.

Methodology

thimbl.com compared the price of the lowest-priced reusable shopping bag available at checkout across major UK supermarket chains.

Prices were taken from retailers' official websites and published pricing information available at the time of research. Where an official product page was not available, recent published reporting was used to support the listed price.

Where multiple reusable shopping bag options were available, the lowest-priced reusable option was used for comparison.