Really great game! I got it at launch for about $30 (Target raincheck deal!).
You can pick it up at EBGames.com used for $26.99 (enter codes CAG15 and SAVER in shopping basket and it would be down to $22.94 shipped plus tax) if you have an EDGE card it goes down to $20.24 shipped before tax.
I've had good experiences with EB they say "Guaranteed to work. Includes instructions and original packaging." You can return or exchange a scratched disc.
If you can wait, this one should go to $30 new pretty soon but with Nintendo its not certain it will go to $20 (like Sony and MS do). But this is a decent EB price if you can't wait.