It doesn't have the same "fun factor" or efficiency, and the fuel storage issues are different, but I picked up a garden variety gasoline generator (10 HP Briggs & Stratton) secondhand through Craigslist a couple of years ago for $300. It was in pretty good condition, and obviously hadn't seen much use.

Prior to purchasing it, we had managed to get by without a generator for over a decade without experiencing any outage long enough to cause us any real hassle. Not long after purchasing this one, though, we had a ~40 hour electrical outage resulting from tropical storm Fay in 2008. The generator saved the contents of our refrigerator and freezer. It's 240 V capable, too, so I could rig it up to run our well pump in a pinch.