Average worldwide price of a Wow subscription is 10$.
Price of a subscription is a lot lower in China and on top of that Blizzard uses a third party to host the servers and provide support, that third party pays them a fee out of the money it collects...
So worldwide revenue is more around 110 million$/month.
One thing not to forget is that there are huge costs associated with those revenue ( except the Chinese ones due to third party taking on the costs).
In the end I would be surprised if the profit per player was above 4$, it's probably less....
Profit of course peaks when expansion are released though...








