Will you have any kitchen access? (You mention fridge space, but that could be a personal mini-fridge, I suppose.)
Buy rice and noodles in bulk, with some beef or chicken stock in jar. All of these are cheap and keep forever, and you can use them as a base for lots of meals. Add some inexpensive fresh veggies in a frying pan or crock pot, and you have something that’ll taste good, be good for you, and be very inexpensive. Fresh carrots, green onions, regular onions, and peppers all keep well. I like tomatoes, too, especially in season. Canned tomatoes are cheaper out of season, and obviously keep forever. Fresh garlic is also something good to have around. Of course, you can add meat (chicken, beef, whatever) to this. Look for sales on canned goods.
(If necessary, you can store the rice and noodles in a cheap rubbermaid container in your room.)
I’m deliberately not trying to give you specific recipes here. You can find those anywhere. One trick is to look at the ingredients in various $1.29 Lipton dried noodle/rice meals in a foil bag. Most of the non-creamy ones are basically 10 cents worth of rice or noodles, together with a few spices and beef or chicken stock. You can make something much healthier and cheaper by adding some fresh veggies to your bulk ingredients.
Dried beans (kidney, black) are also cheap when bought in bulk, but more difficult to use when you’re cooking single meals and have limited freezer space.
Are you a breakfast person? If you eat a lot of cereal, try the bulk route again. Anyone you know have a Costco card? For a healthy (although not cheap) addition, buy a pint of berries. In season, they’re not that bad. Bananas are always inexpensive.
A few other extremely cheap meals that aren’t too disgusting: Canned baked beans on toast. Grilled cheese sandwiches - add tomato slices in season. Substitute canned tomato soup in winter (as a side). Make a few grilled cheeses. wrap them in foil and reheat. They aren’t bad, especially if you splurge a little and buy some better cheeses.
Sandwiches - make them in the morning and eat them for lunch. Bread, lettuce, sliced meat and tomatoes are fairly inexpensive. Toast the bread a bit - avoids soggy sandwich syndrome.
I’m trying to remember what else I ate as a college student. I did eat a lot of pizza.
Will you ever be cooking for more than one? If so, things like pasta sauces (canned diced tomatoes and/or puree, garlic, spices, a bit of beef stock and olive oil, maybe a little chopped green onion and diced bell pepper), omelettes (eggs, diced tomato, cheese, green onions, spices), soups (stock, water, diced chicken or beef, noodles or rice, garlic, spices, a bit of olive oil, and 6 of your favorite chopped vegetables - try onions, peppers, potatoes, carrots, beans and frozen corn or peas) and more adventurous stir frys become more feasible. Also, if you have access to a yard or deck, invest in a cheap $10 k-mart mini-grill. Buy a bag of bamboo skewers. Grill burgers, chicken, or sausage together with marinated veggies on the skewers (peppers, cherry tomatoes, mushrooms) and either baked potatoes or corn (in season - fall). Good stuff.
Spices: In addition to fresh garlic, I’d buy the following in bulk (you’ve got to find a cheap place for spices - supermarket prices blow, and your own taste should guide you. If you like Thai or Mexican, this’ll vary): Black pepper. Oregano. Basil. Bay leaves. Lemon pepper (for marinades). Red pepper flakes. Dried chives. Rosemary. Sage.
Hope this helps. Good luck.