Well... here's some fun articles to thoughtfully read over?
[
x]: How to prevent inflation in a virtual economy?
[
x]: Virtual economic theory in massive multiplayer games.
[
x]: Wikipedia - "Gold Sink"
[
x]: Examples of money sinks in games.
At a base, this framework alone may not be enough to stimulate an economy. Think of creative ways you'd like to handle the economy, and worry about implementation and programming only after you have an outline decently prepared to move forward with. Virtual economies are notoriously difficult to balance.
I will leave you with one last link, to a youtube video!
https://www.youtube.com/watch?v=W39TtF14i8I