My list for basic shopping is normally as follows:-
Fruit- bananas, clementines, apples, anything else on offer
Vegetables - Leeks/potatoes (for soups), peppers, mushrooms, onions, chillis, butternut squash, beansprouts (anything else on offer)
Salad - lettuce, tomato, cucumber, celery
Fridge food - muller lights, cheese, cottage cheese, laughing cow triangles, ham/chicken, bacon, low fat sausages, seafood sticks (sometimes some fresh fish)
Cupboard essentials - passata, chick pea Dahl, beans, spaghetti, tuna, tinned tomatoes, herbs/spices, eggs
Bakery - wholemeal bread rolls, 400g wholemeal loaf
Freezers - mixed veg, chicken pieces, quorn
Hope this helps- this is basically what I bought in asda yesterday for this week and think the bull came to about £30 - they are competing with aldi and a lot of the veg/salad was reasonably cheap!