We bought one last winter for $400 and after a few days work in our living room, my DH sold it to a guy for what we paid for it. It did not do much of anything in our 16ft square living room - the coldest room of the house - windows/patio doors on 3 sides. Our local electric company puts out a "newsletter" every month and they had a special article in it that said to just save your money and buy an electric heater at any store - it uses the same electricity and heats just the same - and costs much less.
HTH