I don't think I would ever play a computer game just to earn $$$ the game still has to be fun and enjoyable to me... I definitely support the idea of being able to sell all your game assets to other players, that way when you decide to stop playing a game you can at least get a little bit of a return on the time you spent playing the game...

I think the first game that I made real $$$ on was Diablo 2, there was a time period when that game was very popular and people started selling items for it on Ebay (and back then I dont think Ebay nor Paypal had any kind of listing nor transfer fees for low dollar transactions...), I had a high level Mage with very high magic find %, I think I ended up making like $100+ in a couple of months, and I would have played the game regardless so it was just a nice bonus...

eventually I think both ebay and blizzard banned the selling of in game items... but it was still fun while it lasted, lol