http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=8701098126&ssPageName=MERC_VIC_ReBay_Pr4_PcY_BIN_IT

Dell Optiplex GX150 PIII 933 256MB 20G DVD Small Form

Just an fyi...
23 hrs left
8 available
$109 + shipping

I bought two for unrelated purpose.
These should make excellent FW's
Will need to buy add'l low profile NIC's
The case has room for two add'l NIC's, for a total of three(3) interfaces

Hope this helps those looking for low cost equipment.

- Don