From my estimates the MMO I'm designing can support 500000 concurrently connected non-idle users (and still be able to you know, do stuff) for about $1700/month in total hosting costs (includes bandwidth). No system admin is needed as the infrastructure auto-scales. Each additional 40000 users costs another $136/month. I've spent several months designing this backend and I'm curious how much other such systems cost.

I should note that this does NOT include the cost of any assets used by the client game. Assume it's an iPhone game with bundled assets.

Thanks!