Configure your blog for Edgeio, post an item and it gets listed, for free. The over/under on eBay buying Edgeio is 6 months.

TechCrunch:

After much anticipation and a period of being available to a private audience the team at Edgeio took the covers off of their creation tonight and launched to the general public. Edgeio takes listings (classifieds) from RSS-enabled sources and organizes them in a central location for users to be able to browse and search. The Edgeio ethos is that content belongs on the edges, and that is where the name originates from (Edge input/output). Content on the edges means the content on the millions of blogs and other sites out there which Edgeio does a good job of aggregating and organizing.