I have a 400-watt modified sine wave inverter from Walmart. It is low quality, but runs a fan, TV or even my refrigerator when on the road. The misleading term "modified sine wave" was invented by advertising people. I call it a "modified square wave."

If you want a GOOD inverter look for a pure sine wave. I own one but it is part of a solar system for the house. (not installed currently). http://www.xantrex.com/power-products/power-inverters/prosine.aspx  is just one you may want to look at. All said, running DC stuff is more efficient