As others have said it is totally possibly to eat healthily without much cooking, I will say that I do eat frozen and prepared foods sometimes but I try to stear away from them unless I am really short on time due to high sodium content.
I love to cook but as a student I really just dont have the time or space to do it so I "cook" but it is very very simple things here are some suggestions.
Smoothies- I use greek yogurt (more protein and thicker) soy milk (you could use cow) and the fruit of my choice that I buy frozen!
Dinners-I also buy a lot of frozen veggies! the ones in the steamer bags are a little more expensive but are so easy and steam up in the mic perfectly. Our grocery chain here even has store brand ones now and they are pretty cheap

Uncle bens ready rice is pretty good and the brown rice is very filling, it is also easy to make a big batch of brown rice and freeze it.
Canned beans are a dieters best friend!! tons of fiber

fills me right up.
I make a big pot of bean soup and can eat that for days with a little whole wheat pasta!
Sometimes for dinner I eat one large sweat potato if I am not in the mood to make much!! if you have never tried them they are soooooo good. and easy to just pop in the oven.
I dont know if you eat eggs but I make tons of omelettes, they have so many veggies in them they sort of turned into veggie scrambles...my fave veggies are bell peppers, onions, spinach and zuchini. i just cook the veggies a little in the pan before adding the egg and right before the egg is done cooking I add some cheese if I have room for the cals!