Promotional price swings mean the exact same product can cost as much as £3 more at one supermarket than another, a new report has found.
Consumer association Which? looked into the prices of thousands of products over six months to find out what was going on.
It discovered shoppers who regularly buy Persil, Andrex and Kenco coffee could be overpaying by almost £3 an item, while even buying own brand is no guarantee that you'll get good value.
Which? head of products Natalie Hitchins said: “While prices will inevitably vary between different supermarkets, shoppers might be shocked to see that they could be overpaying by such significant margins for exactly the same products.
“Most supermarkets use some sneaky pricing tactics from time to time, so pay attention to the prices of your favourite products - and don’t assume you’re getting a good deal just because the item is on offer.”
To carry out its research, Which? looked ar what the same branded products, or similar own brand products cost at Aldi, Asda, Lidl, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose.
These are the biggest gaps it found:
The biggest price gaps on the same items
- Persil Non Biological Washing Liquid (1.33l) - Morrisons £2.98 more than Lidl
- Andrex Supreme Quilts Toilet Tissue (16 rolls) - Waitrose £2.60 more than Morrisons
- Kenco Millicano Coffee (100g) - Waitrose and Ocado more than Aldi
- Hellmann’s Real Squeezy Mayonnaise (705-750ml) - Waitrose £1.87 more than Sainsbury's
- PG Tips Pyramid Tea Bags (240 bags) - Waitrose £1.87 more than Asda
The biggest price gaps on own-brand items
- Cooked and peeled cold water prawns (150g-200g) - Waitrose £3.28 more than Aldi
- Fresh salmon fillets (220g-340g) - Waitrose £2.26 more than Aldi
- Olive oil (1,000ml) - Waitrose £1.81 more than Aldi
- Beef sirloin steak (173-275g) - Waitrose (on Ocado) £1.72 more than Aldi and Lidl
- Chicken korma and pilau rice (400g-500g) Waitrose (on Ocado) £1.51 more than Aldi and Lidl
As well as varying between supermarkets, prices changed heavily over time even at the same chain.
Persil non-bio had the biggest price variation within the same supermarket chain - alternating fairly regularly between £5 and £10 at Morrisons across the six month period.
Which? found the price also varied at several other supermarkets – by as much as £4 at Tesco, £3.50 at Asda and £3 at Ocado.
PG Tips Pyramid tea bags, Twinings English Breakfast and Twinings Every Day Tea Bags, and Andrex Supreme Quilts toilet tissue paper also fluctuated heavily in price at the same chain over time.
Which? said this was a tactic designed to make shoppers think they were getting a good deal when the price dropped, but in fact might mean anyone paying full price is overpaying instead.
For shoppers watching their purse strings, Which? said to keep an eye out for fluctuating prices and potentially dodgy special offers.
