I've been looking around the craigslist for while but the prices for bikes seem to be inflated in SoCal. MOST used bikes go for $150+, never seen anything below that price mark unless there's something wrong with it (chain missing, tires NTB replaced, etc..)

As for $50 offer comment, I think the seller already replaced the tires and tubes, and has tuned up the bike. It would be GREAT if he would sell it for $50 dollars but the replacement he made costs up to the offer.

I'm going to have to go check it out in person and see what'sup.