I purchased the 400watt unit and tested it today, worked perfectly but I still have to test how much it draws powered off.
COBRA CPI-480 400 WATT $18.20
http://www.ebay.com/itm/400674339980?ssPageName=STRK:MEWNX:IT&\_trksid=p3984.m1439.l2649
very nice review on amazon and you can buy a new one for $25
He also sells other units that come in stock from time to time, he sells newer units on his site so I imagine he re-stocks refurbished units a lot
XANTREX XPOWER 1,000 WATT $49
http://www.ebay.com/itm/XANTREX-XPOWER-1-000-WATT-MOBILE-POWER-INVERTER-2-AC-OUTLETS-REFURBISHED/360798564508?rt=nc