I just got a copy of Bomberman Generation used from EBGames online, and not only is it covered with stickers (removed with GG), the cover is messed up from hanging partway out of the plastic sleeve. The disc is only slightly scratched, but has weird white residue all over the inner ring.
My point: It might be worth $1-2 dollars to have a game in good shape, if not for your own satisfaction, for resale value.