A couple of inexpensive ways to heat rooms in your home;
1) Use a paintcan heater. Very easy build and inexpensive. I could explain the directions, but here's a vid link that I've based my builds on;
http://www.youtube.com/watch?v=OPABQW9gN2Q ;They are VERY easy and about $7. to make.
2) Here's another one I saw; I haven't built this one as of yet, but the premise behind it looks to be very sound;
http://www.youtube.com/watch?v=nzKbFzUEWkA
Once you've clicked on either of these links, it will show you other heating ideas for a SHTF scenario at a relatively low cost.