First things first- look closely at the bottom front of the game, see if it says 'promotional copy, not for resale'. See, the original Shadow Hearts was offered as a pre order bonus for the other 2 games, and that version is less desireable, or course.
If it's a proper copy, buy it- $25 isn't a bargain bin price, but it is a good one. If it isn't... good searching can turn up the promo variant a bit cheaper, but not much- I'd still consider jumping on it if you want to play and not just resell.