spaghetti or lasagna. all you need is premade sauce which can be bought cheap in a can , ground beef, and noodles and some kind of cheese. and for a side dish you can buy a prepackaged salad and dresing.
pasta salad: that weird spiral pasta ( sometimes comes in multi colors) black olives ( or green ) italian dressing , cheese, cucumbers.
chicken/tuna salad: chicken/tuna , eggs, mayo , onions, celery, mustard, pepper( yu can also add maccaroni noodles if you want).
theres alot of things you can make yourself for cheap and have plenty left over to last you for a while.