MMO's have always been a net loss for me money wise, but profitable in the entertainment per dollar ratio. The only game I've ever made money on was a mobile Star Wars card game. Dropped around 200 into it over about a year, did a lot of in game trading, wheeled and dealed with the help of a clan mate, and turned around and sold the account for $1300 when I was finally finished with it. Picked a good time to get out too, most of the really valuable cards I had, tanked in value a few months later when they started releasing TFA themed cards that kicked the snot out of a lot of the older stuff.