hello fellow BFs posters, i'm seeking your infinite wisdom.

i'm picking up a 21.5" Trek 800 tomorrow, provided it's in as good condition as described. I'll be using this as a commuter, around town, and campus bike for this fall.

It's being offered for $100, so, assuming that it's in good condition, is that a fair price? it will fit, assuming 21.5".

also, any reviews of this bike as a commuter will be appreciated.