Basically the same way. You can use PayPal for receiving payments or do it the same way that you do on eBay. If you get any of those weird offers of someone wanting to send you more money than you're selling it for or if anything sounds fishy on the deal you can reject it and report it to John (JWN), he'll take care of the problem.
As hard as they try, some of those people slip into the Marketplace.
You can't advertise here in the forums that you have something for sale in the Marketplace or eBay for that matter.