How can I eat healthier while in college?

So I’m a typical college kid and it’s getting towards finals which means 2 things:
1— all of my money for cafe food has run out (this could be a good thing as well as a bad thing)
2— the more I study for finals the more I want to reward myself with unhealthy things like snickers and pepsi

I am an active gym goer so for the most part it counteracts all the horrible things I eat, but I really would like to be leaner and loose a little of the pudge I have aquired. Also I know all of these unhealthy foods aren’t giving me any nutrients or energy which I desperately need now that finals are coming. Anddd if that’s not bad enough on top of not eating healthy my meals are veryyy irregular. Whenever there is an abundance of food (especially free food) I tend to over eat and then my next meal isn’t for hours or until the next day.. This makes me hungry basically all the time.

What simple things (and I say simple because I have NO willpower when it comes to food) can I do to eat healthier in this time of typical indulgence? Any tips or foods that will not break my bank are greatly appreciated.

oh and as a last side note I drink a lot of soda. I know it’s horrible and I’m trying to change that.. it’s a very slow process but I’ve been drinking a lot of water the past few weeks (unless someone knows of another low calorie beverage that is tastey with less sugar and calories)