Wood burning stove is going to be your only realistic option up north here. Nothing else will give you the output/dollar... Pellet stoves are ok, but you're also tied down to using the damn pellets.... Not a real wise option in my opinion as they then have you by the balls if the price of THOSE goes up tooo.
With a regular stove, you can burn just about anything you can stuff (safely, of course) in the thing.
Everything else is too damn expensive. Wood can be had fairly cheaply, and often free, if you know where to look.
It sucks, but that's just the way it is. It's a hell of a lot easier down south, where it doesn't get as brutal cold in the winter.
Unless you like freezing your ass off, there aint many options.
Have you actually spent any time trying to seal up your place and insulate better to KEEP the heat IN ?? You CAN save some loot with a little effort. And now is certainly the time to do it, before winter hits again.....
Even that crappy heat-shrink plastic over your windows can help a bunch. Been there, done that.