From their website:
Listia is a new kind of auction marketplace for giving and getting free stuff. Users list items as auctions, and other users bid on these items using credits instead of money. Credits are earned by signing up, giving away stuff, and being an active member.
How It Works
1. A user lists something they don't want anymore. (like an old TV)
2. Other users bid on the TV using credits they received for signing up, referring friends or listing their own stuff.
3. When the auction ends, the user who bid the highest amount of credits wins!
4. The buyer gets the TV, and the seller gets credits to use for something else on Listia...