There is a interesting blog article with a few general ideas to get you started.
I would say on the most basic level you will need money pools and money sinks. (IE a way to earn money and a way to lose it (preferably one that unavoidable).
I did notice a few suggestions on other forums that suggest making everything craftable and controlling only the basic resources directly (Random placements ores, variable drop rates, spawn points moving (to avoid camping). UBER bosses dropping UBER resources not gear so those that like to craft can still make a living by working for the ones that like to fight :)
Another suggestion was to stop higher level players getting hold of lower level resources directly but making them need it for crafting to ensure the new players have ways to make gold.
In general it depends on the game and the level of complexity you want. You have the economist's wet dream at your fingertips you can see every single transaction,trade and event that occurs.
You could dynamically change prices according to the items demand and supply and players trading prices.
As for the actual question i found a answer here regarding users suggestions however can't recommend any myself (I haven't read them).
Hope this helps