Even college students need occasional breaks beyond winter and summer vacations. Rigorous academic demands leave your mind and body exhausted, especially if you're in the bad habit of pulling all-nighters. If you have a part-time job, you also have to deal with the stress of balancing school and work, and even extracurricular activities can quickly turn into job-like commitments, especially if you've taken on any leadership roles. Simply taking a step out of the bubble and removing yourself from all of the social drama of your campus -- however large or small -- can also help you regain perspective over what you really want to achieve. Vacations are great for resolving all of those issues, but on a poor college student budget, it's hard to make it happen.
Amend your idea of "vacation" before you start planning a getaway. Your vacations for the next few years at least won't be the kinds of trips you took with your parents as a kid. Disneyland, the Rocky Mountains and Europe are out unless you happen to study abroad or attend school at a university located near one of those locations already. Instead, you should focus on day or weekend trips that don't require plane tickets, expensive reservations or even much supplies. Camping trips are a good idea because you don't need a hotel and won't have to eat out in restaurants, and they challenge you in a new way you're not used to. Schedule camping trips around good weather so that you don't need as much supplies, or even a tent.
If you don't want to spend the night outside, consider a day trip to a camp site with hiking trails, a lake, and other activities that don't cost more than the admission to the park, if that. Most entry fees are per car, anyway, so bring friends to split the already cheap cost. You can pack your own food and drinks, and after a day or two canoeing, hiking, swimming and just being outside, you'll feel rejuvenated and more peaceful than when you left campus.
Another practically free "vacation" for college students is a weekend trip home with a friend or roommate. Most parents love welcoming their kids' college friends into their homes, and you'll get to eat lots of great home-cooked food, get a nice bed to sleep in for free, and have the chance to explore a new city with a local tour guide. Even if you spend your weekend watching movies and eating at your friend's favorite restaurants, it's a chance to get away and experience something besides the daily routine on campus.