Old bike from virtually unknown manufacturer with unknown frame (I assume aluminum) ,components/ wheels. Maybe $100 after you've seen it and verified that it's OK? On the other hand, if you check it out and it has full DuraAce groupset, titanium frame, expensive wheelset, then maybe much more. The fact that the guy is an experienced cyclist and yet provides no meaningful description leads me to believe it's low-end stuff he'd rather not mention.