...you don't list a location, but here in my city, we used to sell a reasonably well inspected and repaired (if needed) bicycle that people would give us as donations at pretty down to earth prices. But there were also "project" bikes for sale, and you need to have some idea of what the difference is. Look around for either a bike co-op, or another charity that accepts donated bikes and repairs/resells them to the public. Also canvas your friends, relatives, and acquaintances to see if you might have a mechanical support staff on call.