For super-cheap cooling, open up your case and have a fan blowing on it. One of those clip fans would work well, but if you're going to buy one you might as well pony up a few dollars for some Panaflo L1A's for intake and exhaust. They should still only be a few bucks each.
Err... how do poor students (and other underprivileged people) afford AC? Unless it comes with the dorm? Hehe, oh well.