Ooh, jeez, I forgot Mars Matrix normally runs $30 or more.
But MDK2 and Elemental Gimmick Gear are normally less than $10 (I got my MDK2 for $7 way back when Gamestop was dumping their Dreamcast stuff, not like that helps you though), and there's somebody on eBay right now selling both of them, and a few other games like Grandia 2 and Shenmue:
http://search.ebay.com/_W0QQsassZmember974051