Cheapest supermarket revealed: can Clubcard or Nectar prices beat Aldi?

Aldi was the UK's cheapest supermarket in June 2024 - even when loyalty prices at other supermarkets are taken into account. 

We compared the prices of 65 popular grocery items in June and found that Aldi was the cheapest supermarket (followed closely by Lidl), even when Clubcard and Nectar price promotions were taken into account.

But shopping at Tesco with a Clubcard was cheaper than Asda for our list of groceries. 

Read on to find out how your supermarket compares in the analysis. 

Aldi prices beat Tesco Clubcard 

Every day in June, we checked the prices of 65 popular groceries, including Heinz baked beans, milk and cheese, at eight of the UK's biggest supermarkets to see how they compared.

The chart below shows how much our shopping cost on average:

Aldi was the cheapest overall: our shop cost £118.41 on average, meaning it beat rival discounter Lidl by £2.90. 

But if you shopped at Tesco with a Clubcard, you would get our shopping list cheaper, at £130.90, than if you shopped at Asda (£131.42). 

Shopping with a Sainsbury's Nectar card was slightly more expensive (at £132.90) than Asda.

Lidl, Morrisons and Waitrose do offer some loyalty prices to members of their schemes, but there weren't any on the items in our shopping list this month. Sainsbury's was running Nectar price promotions on 16 of the items on our list, while Tesco had Clubcard prices on 11.

Waitrose was the priciest supermarket again this month, averaging £151.01 - that's £32.60 (28%) more than Aldi.

Of course, price is just one factor when you're deciding which supermarket to shop at. We also survey shoppers on product quality, customer service, store experience, online deliveries and a range of other factors to reveal the best and worst supermarkets.

What about a bigger shopping list? 

When we looked at a much larger selection of 174 items, including more branded groceries, the savings presented by the loyalty schemes were bigger.

Tesco offered Clubcard prices on 84 of the items at some point in the month, and was the cheapest of all the supermarkets included in this bigger analysis (though we couldn't include Aldi or Lidl here as they didn't stock all of the branded items on our list).

Sainsbury's Nectar - which offered loyalty prices on 92 of the items in our sample - came in third.

These results show how much more you'll pay if you're stocking up on a mix of own-brand and branded items at Tesco or Sainsbury's and don't have a loyalty card.

For shoppers without a Nectar card, Sainsbury's came in second most expensive after Waitrose, while for non-Clubcard members Tesco was just behind. Both were more expensive than Ocado. 

• Find out more: how to spend less at the supermarket 

What level of discount do loyalty cards give?

Based on our smaller list of products, having a Clubcard would save you 2.5% at Tesco. At Sainsbury's, you'd save 3.4% with a Nectar card.

But for our longer list, which included more branded groceries and more loyalty discounts, the savings were much more substantial - 7.5% at Tesco and 7.3% at Sainsbury's.

However, you would save even more money by switching to a discount supermarket.

Why and how is Which? now including loyalty prices in the monthly comparison?

Which? has started regularly including loyalty prices for the first time this month. We regularly review the way we analyse and report on prices as we want to give shoppers the most up-to-date and relevant information.

We are only able to take into account loyalty prices that apply to all members of a scheme (rather than those personalised to selected members), where there's one price on the shelf for shoppers with a loyalty card and another for those without. At the minute, this type of two-tier pricing is being used at Lidl, Morrisons, Sainsbury's, Tesco and Waitrose. 

We can’t factor in points, personalised discounts or other rewards as these vary from customer to customer and don't always have a quantifiable monetary value that we could take off the basket totals we report on. 

But while we know many shoppers are members of loyalty schemes and pay the lower prices we're now reporting on, it’s important to be aware that loyalty discounts might not always be quite as good as they seem. Last summer we revealed some dodgy-looking pricing tactics for loyalty pricing at Tesco and Sainsbury’s.

The Competition and Markets Authority is currently investigating grocery loyalty pricing and is due to report its findings in the autumn. 

Some shoppers choose not to join loyalty schemes because they don't want to hand over their data, which retailers often sell to other companies and advertisers.

Our research last summer also found many loyalty schemes have age and address-based restrictions, meaning some shoppers - including vulnerable groups - are unable to join and pay the lower prices on offer to members.

• Find out more: how Which? researches grocery prices

What's happening to grocery prices?

Grocery prices were 2.1% higher in the four weeks to 9 June 2024 compared to the year before, according to market analysts Kantar. That's the 16th month in a row grocery price inflation has fallen.

Poor weather affected sales with consumers buying nearly 25% fewer sun care items compared with the same time last year, while prepared salads dipped by 11%.

Prices are rising fastest in markets such as vitamins, minerals and supplements, chilled fruit juices and drinks and chocolate confectionery. They are falling fastest for toilet tissue, butter and milk.

• Find out more: Which? food and drink inflation tracker