There is one PPC mac i still use every day, my Xserve G4. Love that thing cost me £65 (inc shipping) runs all my public services (2 instances of HTTP, one of FTP, one of wired and one of KDX.) Allong with all my torrent downloads, TM backups and backups of all my xbox games. I'm gonna run that thing untill there is no way i can get spares for it, then i'll get a xserve G5

(I was gonna get a Xserve G5, but i'm 15, so there was no way i could afford one of those)
you are lucky, it cost me £50 (with shipping) for two disk sleds for my Xserve G4 (bringing the total for it up to £115)