Wow, thanks for the very informative answer!
It's amazing how hard it is to find easy to understand information about this stuff.
Just out of curiosity, how did you go from the 746 watts to 220? Or was 220 just an educated guess?
I've looked around on Newegg and Amazon, and it seems like the cheapest pure sine wave one would be the CyberPower 510W
. It's $115, but it seems to be the lowest wattage of the pure sine type.