generator is prolly the best way to go, but you can take a car battery and put a power inverter on it. the best battery to do it with, though, is a deep cycle marine battery, but they are $100 or more
We've always used a 12 volt car battery with an inverter. 1 car battery will run a TV and radio for 5-6 hours. The whole setup will cost you around $120.
Those silent generators are great if you do not mind dropping some bones to get one.
However if you want to save some money this is the Generator we use. It is 1200W and not loud at all about like an idling weed eater. It will easily run a tv and stereo plus other utilities.