Eve Online is the MMO that has got this closest to right. The economy has been running for 10 years now and inflation, whilst existing, has not been rampant.

Eve Online is the MMO that has got this closest to right. The economy has been running for 10 years now and inflation, whilst existing, has not been rampant. Interestingly, there is not a RMAH, but there is a system to exchange ISK (gold) for subscription time that someone else bought. In other words the conversion of cash to ISK is facillitated - but not ISK to cash.