Ooh, nice find with Monster Rancher 2. That's probably my favorite PS1 game. It's the reason why I don't throw away ANY CD's. I've got spindles full of hundreds of AOL trials, travel DVD's, and more. I know you can just burn a special CD to get whatever monster you want, but it was so much more fun to be surprised.
Was this the SA on Ming by any chance? That's the only one I ever see with games. Goodwill usually has a good selection (especially the one by Winco on Coffee Rd.), but they usually charge too much.