Searching a script for exchanging goods

Hi Guys

I want to make a homepage to exchange goods in my country. Does anybody now a finished script for that?
It is actually something like ebay. But instead of an auction and people buying it they can get in contact with each other and exchange goods.

I'm happy about any tip.

thanks

I don't know how good this one is but it came up in a search:

Thank you very much for your help. But his looks a little bit dodgy to me;-) I hoped there would be something finished out there. So I probably have no choice than to write it myself.