It depends on what you like.
Pasta, and tinned or jar pasta sauce (both red and white).
Bread.
Cheese.
Eggs if you use them fast enough.
Rice (precooked pouch or frozen; minute; Basmati).
Tuna or salmon in a can.
I try to keep a bag-o-meal in the freezer, as they’re cheap and 10 minute fix.
Tinned mushrooms, black olives and tomatoes.
I seem to recall that you don’t like to cook much and have a limited budget, so pick your favorite foods and look for cheap, convenient ways to throw them together.
You can take frozen boneless chicken breast or fish fillets, put it in a baking dish with a covering of pasta sauce and tinned toppings of your choice, serve with rice or noodles and have a great meal in under 40 minutes.