Research from personal finance comparison site Finder.com found that Sainsbury’s has the lowest value loyalty points system. To save enough points to pay for a weekly shop, a Sainsbury’s loyalty card owner would have so spend an eye-watering £12,440.

The study revealed that it would take three years and ten months to reach that point based on a weekly shop that reached £62.20.

Loyalty points from Morrisons and Tesco are worth twice as much as those from Sainsbury’s. Shoppers would need to spend £6,220 to get enough points to pay for one week’s groceries at either of those supermarkets.

The Co-op provides the best deal at £3,110.

Loyalty not well rewarded but still popular

Yet supermarket loyalty cards are still a popular method of saving, as 92% of those quizzed said that had at least one card.

Despite the time and money needed to redeem loyalty points at UK supermarkets, a total of 64% of loyalty card holders said they signed up to earn points for future spending. Also 44% of those who took part in the survey said that signed up to loyalty schemes to qualify for discounted prices.

Card changes mean different savings

Recently, many supermarkets have changed tack in offering customers loyalty schemes for member-only discounted prices, rather than a points-based system.

In response, Finder tracked the loyalty and non-loyalty prices of products at Sainsbury’s and Tesco over two weeks during June.

The investigation revealed that regular prices at Sainsbury’s were 45% higher on average than the Nectar prices. While, at Tesco, the difference was smaller as its prices were 36% higher on average than its Clubcard prices.

Finder also noted that some products had changed price before and after being on offer, saying that this was ‘potentially to increase the perceived savings of having a loyalty card at that store.’ For example, a tin of tuna chunks at Sainsbury’s had a regular price of £5, and then was reduced to £3.75. Once the offer stopped the regular price fell to £4.50.

Over £1,600 to buy a jar of coffee with Sainsbury’s loyalty card

Finder’s research also looked at how many points are necessary to purchase individual items with a loyalty card. It found that Sainsbury loyalty card shoppers would need to spend £1,620 just to buy a single jar of coffee with the points system. This total compared unfavourably with Tesco’s where £600 would be needed for a coffee jar.

However, both figures highlight just how expensive  to reap any membership rewards.

‘Can customers afford to shop without loyalty cards?’

Liz Edwards, editor-in-chief at finder.com, said: “With the cost-of-living crisis taking its toll on consumers, there’s now more pressure than ever for supermarkets to give back to their customers wherever they can, and loyalty schemes have become crucial for many families to help them pay for their weekly shop.

“However, our research shows that customers would have to spend a huge amount of money to earn enough points to buy even a small item.

“Our survey also revealed that 55% of loyalty card holders signed up to earn points that they could put towards vouchers for restaurants, travel, hotels or accommodation. However, Tesco recently announced that these points will now only be worth twice the Clubcard voucher value, instead of three times as they used to be. This is another blow to customers who have come to rely on these vouchers over the years.”

“UK supermarkets are clearly shifting the focus of their loyalty schemes towards discounted prices over earning points. We found that some non-loyalty prices were far higher at certain supermarkets than the regular price at others.

“This could therefore be seen as a penalty for those who don’t have a Nectar card, and begs the question: can consumers afford to shop in the UK without loyalty cards? By signing up to these schemes you’re granting these supermarkets access to a wealth of information about your lifestyle and shopping habits, and this might not be something that everyone feels comfortable doing.”

Tesco and Sainsbury’s have been approached for comment.