See if there's a bike coop in your area liek we've recently developed ( www.thebikeproject.org ) - you can get a used bike but you can also join for 25 bucks, then choose from the inventory of abandoned bicycles (the U. and local police let us have them), and fix it up - which sometimes takes very little - and get it for even cheaper.
Alas, we've had lots of students come down because their bicycles were stolen. At our esteemed U, bicycle parking ranges from lousy to nonexistent and bikes aren't even allowed in dorms.
You might also consider a folding bike (which here you can sneak into dorms ) .