Buying the game

So, I used to love this game as a kid. My younger brother recently got into it, and I'd love to play a few multiplayer matches against him. However, I've been unable to find this game for anything cheaper than 40 euro's. That seems like a ridiculous price to me. Why is the price still this high, and is there any way to get a discount? I was hoping the Halloween sale on Steam might do it, but it's not even discounted!