I once had a Cloak of Flames in Everquest.
I exchanged it for $1075.
That's a lot of apples!
I bet they were really good apples too!
Seriously though, money is a medium of exchange as much as anything else, all you need are willing participants.
In example, I'm trying to get a second job in a head shop as manager there, so I can introduce that community to bitcoins and provide a way for the customers to pay with bitcoins.