I've got one on eBay right now.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200400351572&ssPageName=ADME:L:LCA:US:1123 They seem to go for around $250 (plus or minus $25) on eBay lately.
I'm selling my 3000 & keeping my 500 because it's more compatible with the games I like to play. Although I'm interested in maybe picking up a 2000 someday.
The 3000 I'm selling has a couple expansion cards, 7 meg memory & a 2.1Gig SCSI hard drive. It has 2 days to go & so far the bidding is just over $150.