An excellent Idea. To start what about a way that all players can make one or two real items themselves, approved of course. That way we could generate a whole stock of items that we could then circulate. Items should cost between 1 - 5 silver coins, as many players don't have siver it would slow down trading considerably, as metioned silver is mostly owned by the upper class of MD and it is hard to obtain, mostly through quests. Maybe 1 silver coin could be given to players who complete the Loreroot guards or the Willows guards for example. A barter system would be other option, item for an item. Items should have full descriptions and be classifed as common, uncommon and rare. With rare perhaps only one or two being available but others can be create by a smith or artisian at the cost of more silver.
Hope this works for you Kriskah.
Best
Macnia