Rusty, if your university is within a reasonable distance of an active flying club, the notice board should feature a few shares going from time to time, particularly in types operated on Permits. Relatively inexpensive shares may also be seen advertised in the PFA magazine or on the PFA website. The thing to check on, through talking to group members, asking local PFA people, etc. is whether or not the inexpensive aircraft has been looked after on too much of the cheap, as may sometimes happen. If it has, you probably don't want to get involved. There are, however, a reasonable number of honest, well maintained Cubs, Jodels, Condors, Aircampers etc. around, as well as the various single seaters (Lutons, Nippers, that sort of thing). The capital outlay required may be sufficiently low that a few years on you need not greatly worry about whether or not you can recover your share price. There's always the microlight world, although I know little about that.
The friend I mentioned was lucky in blagging his way into a certain amount of inexpensive or even free flying through contacts in the Tiger Club and other organisations. That was in the 80s, and there is probably less of that available now, but a bit of schmoozing around the local grassroots flying community might still reveal some opportunities.
Where will you be studying?