How do we escape the cycle of bad college eating?
I'm in the same situation as you are, I'm a college student on a budget. What you need to do is convince yourself that it's better to cook your own food. I accomplish this by tracking how much I spend on food at the grocery store each week, and comparing it to buying fast food. I've been doing this since Summer of 2010 and trust me, cooking yourself is a lot cheaper. Per day, I spend about the same that I would on one meal (pizza, whatever), only that includes breakfast, dinner, snacks, etc. If you track it yourself, you will quickly find it's more expensive to eat out, although it is convenient. 

I also make a list of meals I would like for the week (I shop a week at a time), and use this list when purchasing and stick to it. You'll find that when you follow recipes, you can make a lot of substitutions for what you have on hand instead of having to buy another ingredient. 

To avoid losing ingredients, just stick them in the freezer! Meat, vegetables, whatever you're buying, most of it can be frozen. And frozen stuff lasts for weeks (minimum). Leftovers can be frozen too. When whole chickens are on sale for example, I buy them up (2-3 at a time) and freeze them until needed. 

The worst thing I find is (as you've probably seen) the time commitment. It takes time, but you if you cook more you get better at it. 

I also find that the less "processed" food is, the cheaper it is. For example, buy whole chicken or split chicken breasts instead of boneless/skinless/etc. and cut it up yourself. Look for the "reduced price" meats when their sell-by date is close to expiring, and freeze them. They are fine. Buy potatoes, canned vegetables, and avoid meals that come in a box! They seem cheap but they are more expensive than what you can do yourself. 

... and finally, the real motivation (for me at least) is that I got sick of the options available around campus. If you make your own food, you're not limited by a menu and eventually it will taste better!