This is a good time to starting checking around campus for used bikes. If your university is like most finals are almost upon you and some students will be graduating and moving on and looking to sell their bikes so now is a great time to be looking. My University has a great program where they buy bikes from students for $20, fix them up and then re-sell them for the same price. Yours might have something similar ask around. Check the bulletin boards in the dorms. You could also put up some bike wanted signs.