Supermarket multi-buy deals can end up not saving consumers money, according to a new report.
Consumer watchdog Which? monitored more than 100 products on sale over the course of a year at Britain’s biggest supermarkets.
It found that around 10% of products became more expensive on multi-buy deals, some deals did not offer any saving at all and some products were almost permanently on discount or multi-buy.
One example was Goodfella’s Deep Pan Baked Pepperoni Pizza, which more than doubled in price at Asda when it was on offer.
Another was Nestle Munch Bunch Yogurt at Tesco and Sainsbury’s which, over a year, was either £1 or two-for-£2 - meaning either way the yogurt still cost the same.
Waitrose was also accused of having misleading offers in their stores.
"With household budgets squeezed and rising food costs among the top worries for consumers, it’s all the more important that stores make it as easy as possible for people to spot the best value products," Which? said in a statement.
Multi-buy deals have become increasingly popular with Britain's largest supermarkets. Out of 115 products looked at by Which? 43% were on offer during the first part of 2012.
But it seems the public are getting wise to this kind of pricing tactic - with 73% of those asked saying they prefer discounts to multi-buy offers.
Food shop is among consumers' biggest weekly expenses, with increases in food prices seen as the second largest contributor to last week’s rise in inflation.
However, supermarkets have defended their promotions strategies.
"Customers tell us they want low prices, not a strategy that gives with one hand and takes with the other, we're making sure the cost of the weekly shop is consistently low, with no surprises," Asda said.
Meanwhile Sainsbury’s added: "We never seek to mislead our customers."