The Samlex NTX-3000-12 inverter will take a 6000 watt surge and run at 3000 happily for less than a Canuck boat buck. (Designed here in BC.)
Their PST-3000-12 has more bells and whistles, can be hard wired and, I believe, is heavier duty.
I've been using 2 of their inverters for 5 or 6 years...