Me too! I just bought a new Marin Larkspur this week for commuting and general riding (lovely bike!), but wanted a "newer older" utility bike to replace my in-need-of-major-overhaul 30-year old Motobecane for groceries and nearby errands and anytime I don't want to worry about locking the new bike up in a questionable place.
I went out to a block sale in my neighborhood yesterday morning and happened on a Trek 800 Mountain Track. The price? $12.
No rust at all, just in need of a new seat and some new grips; I brought it home, pumped up the tires, wrapped over the old grips with some foam handlebar tape I had, put on an extra seat I had laying around, and took it for a spin. It works flawlessly, is rock-solid, and appears to need nothing more than a clean-and-lube.
I don't know much about the bike--trying to find out when it was made--but it seems perfect for what I need and I'm delighted with it. The best $12 I've spent recently, for sure.