Ends today. Newegg has the Rosewill RCI-400MS 400W DC To AC Power Inverter with Power Protection and Alarming for $30 - $10 off with coupon code EMCNCHD87
[Exp 8/1] = $20
with free shipping. Converts 12 volt DC power into a 120VAC outlet, includes battery terminal clips, and features overload, short, and a low voltage audible alarm.