Buy it used.
Second, the story line. First off, WOW, it was really bad, if you haven't watched the movie, watch if before you play this game, because the story in this game is so bad, i cant even believe it. They totally rip it apart and stomp on it with their feet! They also try to make it funny, like when Jinny takes the book from Harry, she just throws it, pathetic! Also, the ending is so easy, its not even fun.
Third, the gameplay. It really needs more spells, you can only use like 4... The running is annoying because if you hit someone you fall onto the ground and sit there for like 10 second before getting up.
Fourth, Quidditch. That was a letdown too. I was looking forward to some heart pounding quaffule action and throwing it into the hoops. And you know what the hell it is? Its dumb seeker action. You start off with the seeker right in front of you and all you have to do is hit dummies and stars with your broom, you don't even do the turning! And i was looking forward to that...
Fifth, the Dueling ring. OK, i guess,its just like fighting someone except on a stage...
Sixth, the potion making. I was looking forward to this too, and all it is is first grade follow the colors and shapes. A big letdown there too.
Seventh, the Crest. What a waste of time! Having to look all over the school for these dumb crests is boring!
But somehow i keep playing this game. If you are a harry potter fan, this game will just make you keep playing. I recommend buying a used one if you know whats good for your wallet...