We have two different size Inverters.
We have a 1200 watt Inverter that we bought at a Black and Decker outlet store for $59.
We don't carry a microwave
. Though we've never run a microwave
off of it, I suspect it could run a small, 700 watt microwave. We have used it to run just about everything else including an 4 cubic foot AC Fridge
You should know that running a microwave off an Inverter/Battery combination will be a serious draw on your battery
. If the microwave draws 6 amps AC; it will draw 60 amps DC from your battery
. Generally not a wise situation unless you're just running the microwave for short periods.
For smaller things like running our computer, charging cell phones or running our LCD TV, we use a small 100 watt cigarette lighter Inverter. We actually carry two of them, one in the tow vehicle and one in the trailer. They cost about $20 each. They are very handy to have.
The small inverters typically only have one outlet so we often plug in a 3 position expander.
The problem of with running a big 1200 watt Inverter for small things is that a big Inverter is inefficient for light
loads; hence the small inverters.
Hope that helps