GT Tachyon crossover.

[batmick]

It's not an MTB but it's not a road bike either. It is retro however and cheap.

http://sandiego.craigslist.org/ssd/bik/1577065627.html

Even has a U-brake and the flip-flop stem.

 

[yo-Nate-y]

That's really cool and cheap too. If I were in Southern California I'd grab it. T'would make a great commuter.

 

[SeeingisBelievingGTMuseum]

That's a monster 22"er. Have two just like it one in Midnight Aurora and one in Purple...but have the 2.0 tires on them. I found one mixed in a listing with a cloths washer and dryer for $65 and it's in much better shape than the one in this listing.