A general food shop for me is Porridge oats, bagels, peanut butter, bananas, brocolli, blueberries, spinach, chicken breasts (can't be arsed messing about with chicken on the bone), greek yoghurt, chorizo, feta cheese, cous cous. I shop at Aldi so don't know too much about healthy stuff at Sainsbury's.
By far the easiest/good meal I eat every day has to be a tin of tuna with cous cous and chopped feta cheese in a bowl together. A little bit of boiling water for the cous cous mix in the tuna and feta and hey presto.