Bust A Groove Playstation

I have quite a few game systems in my room and play them often. I havent played my playstation in years and there is a certain game that I have been searching for to play on it. Bust A Groove was a really fun gave but came out in 1998 before the DDR craze. I see it on ebay and other auction sites for over $100. Does anyone happen to know where I could get a used copy of Bust a Groove and Bust A Groove 2 for under 100? I would never spend that much on any game old or new!
If ANYONE has ANY info on finding these games in stores or online please tell me any info is greatly greatly appreciated...I WANT THESE GAMES.