I purchased Esvon classified software a while ago and never really used it..
http://www.esvon.com/pg/products/p_classifieds/
It cost me $649, before I purchased addons to integrate it into vbulletin, and search by zip code. I can still login to esvon and download the software, but I have no idea how to transfer the software to a new owner.
I want to start the bidding at $99, and will take offers north of that for a "buy it now". Let me know if you have any other questions.