This might possibly be the latest reply to a thread in forum history, but I thought I'd get back to you anyway.
We did have a marketplace on the forum a while back. You could buy/sell/trade items, and make off hour requests for others. It turned out to not be as popular as we had hoped. It was on the forum for about a year before we removed it. If there is increased interest in the future I will re-visit the idea with Sarah the DM.
Cheers,
-Wheatonrunner69