Found these tonight while cleaning out some boxes downstairs:

July 2000 - Volume 6
September 2000 - Volume 7
November 2000 - Volume 8

Discs are lightly scratched and September has a crease in the top right corner. I think I received these in a box of DC games at a pawn shop last year. I don't collect the demo titles nor keep up with prices so I'd appreciate if someone can give me some insight. eBay prices on similar discs are sporadic as usual and unless these three are highly desirable/valuable, I'm throwing them in my Dreamcast box tomorrow.