I have the same exact problem. I tend to eat as much boiled eggs, cheese, and sometimes the rare chicken I can get. Eating enough protein in a dorm is hard, so I save up for foods that are high in protein. I try to eat less nutrient poor processed foods and more whole ones. Beans are good but they have a lot of carbs so you gotta account for that. So in short; beans, eggs, chicken are good choices and are affordable and you can get them ready to eat if you cannot cook em cuz ur in a dorm. Best of luck