The Bitmessage network is used for posts and buyer/seller communication and the Bitcoin network is used for payments. The app connects to those networks using the location hiding Tor network.

The seller puts up 1x price of item as a deposit and buyer puts up 1x for deposit + 1x for payment. These can only be released when both agree on payment or refund. This keeps incentives aligned without the need for escrow agents or reputation systems.

Free client, no fees, no altcoin. Open source code available on Github under an MIT license. Posts go directly to the Bitmessage network and are therefore uncensorable.