Thanks. Damn, I barely got it at that price. I was looking for anything around $11 to get free shipping. I decided on a 16 GB low profile thumbdrive for $12. I'll put my music on it instead of sharing one of my 32 GB thumbdrives with non-Xbox 360 files.
Just before I confirmed my order I checked the game's webpage to see if it was still in stock. It went up to $22. I tried to confirm my order anyway, and the game did sell for $15. If it was just in my cart, and I wasn't in the checkout process, I don't think the price would have stuck.