I say just go to a thrift store, salvation army, goodwill, whatever. Buy an old bike for pennys (most under 10$ here), either fix it up yourself, or pay your LBS 100$ for the overhaul tune-up. Just steer clear of the same brands of bike you would find at Target, Wallyworld etc, cause they really aren't worth fixing up.

Or even more fun, just convert the bike to SS or Fixed, cause once you get fixed its a irreversable operation.