The everyday supermarket essentials you should never pay full price for

We all know that your choice of supermarket makes a difference to the price of your groceries.

Each month, the team at Which? reveal the cheapest retailers, with Aldi regularly taking the crown and Lidl following not far behind.

However, the findings of their latest investigation suggest that it’s not just where you shop that matters, but also when.

The consumer champions delved into supermarket promotional strategies and found that some of the UK’s favourite branded products are on offer so often that shoppers should never be paying full price for them.

Which? kept track of the prices of thousands of popular groceries from March 2025 to March 2026 at Asda, Morrisons, Ocado, Sainsbury’s, Tesco, and Waitrose.

While doing so, they claim to have identified ‘clear patterns’ of rotating three-to-four-week discount cycles.

This means shoppers could be paying ‘over the odds’ for popular items when they are not on promotion, as they are most likely on offer somewhere else. 

Several grocery staples, such as Kellogg’s Special K cereal, Tropicana Orange Juice, and Fox’s Chocolate Biscuits, were found to be on offer at one major supermarket or another every single day of the year.

The experts at Which? said this discovery was particularly ‘alarming’, explaining: ‘The sheer amount of time individual supermarkets kept these items on promotion highlights why shoppers should take the listed “full price” with a pinch of salt.’

According to the findings, a 440g box of Special K consistently sat at a full price of £3.30 to £3.50. But if you were to shop around, you could buy it for £2.85 or less somewhere else every single day of the year.

Ocado had the cereal on offer most frequently, as they sold it on promotion 51 per cent of the time. This was closely followed by Tesco at 50 per cent, and Waitrose at 48 per cent. 

Discounts on Special K were less frequent at Asda and Morrisons, but the cereal was still discounted in these stores 29 per cent of the time, when the price dropped as low as £2.63.

Tropicana Orange Juice (1.5L), which costs between £4.28 and £4.75 at full price, was also discounted to £3.50 or less 99 per cent of the year. While Fox’s Chocolatey Milk Chocolate Biscuit Rounds (130g) were on offer for 99 per cent of the year, costing £1.75 or less, instead of £2 to £2.75. 

Other examples included Nestlé Shredded Wheat Cereal (625g), which was available at a discounted price of £3 or less 97 per cent of the time. 

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Onken Set Natural Yogurt (450g) was also consistently marked down throughout the year, as were Kettle Chips Lightly Salted Crisps (130g).

The investigation also uncovered ‘extreme’ price swings on branded items in supermarkets.

One of the most notable was a four-pack of Light & Free Peach Passion Fruit Greek Style Yogurt. The price is said to have fluctuated by 190 per cent, costing £1 at Ocado at its lowest and £2.90 at Waitrose at the highest.

Asda had the single biggest price hike within the same store, on Amaara plain poppadoms (200g). These cost just 48p at their lowest, but jumped to £1.50 at a different point in the year.

Despite this, Asda currently remains the cheapest supermarket for buying branded groceries, according to Which’s monthly price monitor.

Reena Sewraz, Which? retail editor, said: ‘Supermarkets are using dizzying pricing cycles to create a false sense of urgency, but our investigation blows the lid off these endless promotions.

‘When items like Tropicana and Special K are on sale nearly every single day of the year, the “full price” becomes entirely meaningless.’ 

She adds: ‘To avoid being ripped off, shoppers need to ignore the flashy promotions and look closely at the unit pricing on the shelf edge – the price per 100g or 100ml – to see what they are actually getting for their money. 

‘If you are loyal to a certain branded item, it could be worth tracking prices across multiple stores and stocking up when you see a good deal.’