I'm from the UK but in Australia, and I sometimes shop for family back in the UK online and can't believe the amazing prices there are in the shops.
Conversely, I'm also staggered by things like 3 fingers of watermelon costing 50p, plus the amount of packaging.
I think in Australia we tend to shop much more seasonally and package less, definitely there's no ready meal culture (well there is, but it's very boutique and expensive).
Can I ask what you pay for in your country for staples such as :
1kg potatoes
500g butter
1/4 watermelon
Punnet of raspberries
Bottle of NZ Sauvignon Blanc Wine
2 free range chicken breasts
Pint of milk
1 whole cauliflower
Butter
Tin of crushed tomatoes
500g mince
Loaf of bread
And
UK import of something like Fry's Chocolate Cream or Baxters Soup