Just a note--GameStop is not really selling it. Yes, they have low on-line prices, but not that it's perpetually "not available." Their in-store prices are, AFAIK, much higher, if you can even find it. This is true for a lot of retailers--just a few months ago Wal*Mart had it for full price in stores, yet on-line had it for $30 (the SE, that is, which is about the price Amazon.com has been selling it for in the US). I got it for $25 on Amazon a few months back, and I haven't seen it cheaper many places.
If you like to browse brick and mortar game stores, you might find it cheaper in a bargain bin from time to time. I had no luck with that personally.