Heat Sensibly

Make sure that you are heating an area with the appropriate heater.  If you have a tiny heater, don't try to heat the whole house with it, or even a room with it - it's designed for a very small area.  It's more economical long term to have heaters of the three sizes you need - a tiny one to keep your heat warm, a room heater and a larger area heater (although it is better if you can move your room one around)  I have a room heater and it is on wheels so I just move it to the next room when I am going to be in there for an extended period of time.  I've saved a lot using this method.