Have a look at autoscout24.ch to give yourself an idea of going prices. But it's a buyers market at the moment, so you should be able to find something. If you know anything about cars, you might want to try the car section of Ricardo, Swiss auction site - but be sure to arrange to look before bidding.

Oh, and look for a car that has been tested, i.e. "ab MFK" (Motorfahrzeugkontrolle).