If you went into four different major supermarkets on the same day and bought exactly the same trolley full of shopping - a week's worth of groceries - you may expect the cost to be roughly the same.
We tried just that, taking a identical list and buyng the identical brands at Tesco, Asda, Sainsbury's and Morrisons to figure out exactly which is cheaper.
The results are surprising - with the most expensive probably not the shop you were expecting.
And the difference in price is more than £5 on an average week's shopping for a family of four.
The Echo sent a reporter out to try shopping at four different chains
The shopping list included items which most shoppers are likely to buy on a regular basis alongside some 'luxury' items.
We bought:
Warburtons Toastie White Bread
Four pints of British semi-skimmed milk
Six large free range eggs
Fairy Liquid (Original)
Andrex Classic Clean toilet rolls
Clover Spread (500g)
Tins of Heniz Baked Beans (four pack)
Potatoes
500g Penne Pasta
Ham slices (around 400G)
Chicken and Mushroom pot noodle
Old El Paso Mexican Original Smoky BBQ Fajita kit
Blueberries (200G)
SmirnOff Vodka (1L)
Domestos Original Bleach (750ML)
McVities Digestives Milk Chocolate (266G)
Cathedral City Mature Cheddar Cheese (350G)
Lemon Drizzle cake (Own brand)
Multi pack of Walkers Salt and Vinegar crisps (six pack)
Heinz Tomato Ketchup (250G)
Asda
Total food shop amount: £50.99
Tesco
Total food shop amount: £52.88
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Morrisons
Total food shop amount: £56.32
Sainsbury's
Total food shop amount: £54.20
