We realize an answer that requires more money to solve your problem is missing the big picture, but we'll start by recommending a few books:

Of the three, we're most familiar with The Healthy College Cookbook, written by actual college students, and which is more focused on nutrition than the other two books. All of them have suggestions for cooking in small quantities and on a budget, and a surprising number of recipes that call for four or five or six ingredients.

Among the snacks that these books suggest are: Ants on a Log (celery sticks stuffed with peanut butter and topped with raisins); a hummus sandwich; endive leaves stuffed with low-fat cream cheese mixed with a little oregano, basil, salt & pepper; a tomato & pesto sandwich; English muffin pizza with all variety of toppings; a chagel (a split bagel topped with a firmly scrambled egg, topped with mozzarella cheese and melted under a broiler or in the microwave); cottage cheese on a bagel; a tuna melt; a banana shake; baked bean rarebit (butter, cheese, milk, dry mustard, baked beans, and an egg, mixed, cooked and served over toast); a version of home fries; a tomato, onion and cheese casserole; and waffles.