Sometimes it's good to live in the Silicon Valley, but Ebay works pretty well. I have yet to be disappointed by an Ebay purchase. My SCSI chain is SCSI-II UW, but since U2W has largely taken over it's easy to get enormous SCSI-II drives for cheap ($88 for a new 18GB drive that's fast enough to give Pro/Engineer a crunchy feel). My DDS-3 tape drive is from Ebay, $175. For these prices you can afford to take a couple of chances.
Halted Specialties, known to many Silicon Valley development types, sells, well, junk. But the junk often works well enough to get things done. I buy a lot of odds and ends there.
If you have to send away for stuff you can do a lot worse than to check
Reseller Ratings before you buy anything.