If your bike gets a lot of use, it needs regular repairs and tune-ups. Bike repair stands aren't free, but biking weblog The Pedal Pusher has a solution that's far from expensive.
You'll need some pipe, a couple of 2x4s to make the seat post clamp, and a few small miscellaneous items like hinges and flanges. The project isn't difficult — it really just requires screwing a bunch of pieces together. And, best of all, it should work out to be much cheaper than buying a stand from a bike shop.