Depends on the barebones package
I was just shopping around and checked out the "barebones" packages over at
gamepc and they were outrageously priced.
I just bought an MSI Nforce board w/ integrated video, sound, and NIC, plus a retail Athlon XP 1600 CPU, a 300 Sparkle PS, and half a gig of DDR ram for under $500 shipped to my door.
All I need to do is add a HD, floppy, CDROM, and Case for another $200 and that's a dang nice system for under $700.
How much $$ are you thinking on spending?