OK bike ignoramus here: I'm trying to buy one and avoid getting ripped off in the process. I found this for $50 on craigslist:
Leisure bike. Has always been well maintained and has almost never been used.
Brand: Schwinn, Type: Suburban. Frame height: 20". Seat height from ground: 34" lowest, 45" highest. Tires: 27 x 1 1/4 90PSI