They use wood pellets. These can be bought online and drop shipped to you by the ton or bag. You can go to TSC or lowes maybe and buy them there as well or any stove store. Folks say its constant heat and in a good insulated home can be all you need.
I think in the future as more mills open the price may fall as demand increases as does supply. Some stoves burn pellets only some burn corn, yes a dry corn kernal, for fuel and some burn both.
Both type pellet stoves do not have cats, and can vent directly behind themselves if on an outside wall through a 3" steel pipe. Only exhaust is heat and water and CO really. There very clean burning, but like folks said you HAVE to have power to get any operation, they have fans to push heat an auger to move pellets an igniter i think? as well as some i think have an exhaust fan? My wood stove should not be burned wide open with out blower but can on a lower setting, and i can always leave the door open and use it like a fireplace as well. I can heat without power a smaller portion of the home with the wood stove, but i have a generator so thats not my problem. I sit there blower going fire wide open in my warm house, watching my satellite tv.