Create a buyer/lister escrow bidding system (like this site)

I need a function on my Joomla website that lets users put money in an escrow account. Also I need users to be able to bid and create projects and to post messages to the user (just like this site [login to view URL]) almost exactly mirroring it. I have the design and content completed so It shouldn't be a huge job. Just a little programming. Thank you.