A LOT of people have asked about a 'marketplace' type component on here. A LOT. Unfortunately it's not nearly as easy as you might think to code something like that. I don't know anything about CoinGate (which may be simpler, as it deals with crypto based on the 10 second skim of the site I did), but integrating with more traditional APIs for payment like Dwolla or Paypal is quite time consuming to do for a php application. A marketplace component would be great imo, but good luck finding someone willing to code it for free/cheap.