Yeh, heard some good stuff so far....
As a university student, I can definitely relate on the "inexpensive" part.
Basically, I eat a ****-ton of fresh fruits and vegetables. They don't have to be fancy, no need to break the bank, my primary snack foods are apples, pears, and carrots.
And eat whole foods, rather than processed foods. Quinoa is great, especially if it's cheap where you live (not cheap where I live
) ; lentils are a staple, I don't eat of brown rice but it goes in this category. Veggies all cooked together in various ways, lots of curry spices. As you'll find out if you read around here enough, curry spices are all quite good for you! AND they taste great.
My dessert is frequently chocolate, and I use honey as a sugar when making sweet things. And get some real salt, goddamnit! It'll make your life better. There's a health food store back home that sold bulk Brittany sea salt for almost nothing, it was chunky and greenish. GET SOME LIKE IT!
The trick is making sure what you eat is REAL FOOD. Not a food-like substance that's been packaged and labeled "healthy".
(see Michael Pollan)
Fractal should show up and give you the low-down on how to be really hardcore, but that's my take on it.