Use that link, then buy it.
The price right now is $44.96, then use that link to bring it down 15% off. Of course this is only for the PC version. If you buy it from Direct2Drive you do get the "Psycho Pack" with your purchase.
Enjoy! I know I bought a copy as soon as I seen this.
Edit: I wrote it wrong in the topic. Its only 15% off. Sorry guys. Either way, I already bought it! haha.