Modification ideas for boondocking

The thought of dual pane windows intrigued me...... until I looked them up on google and found that each window was going to cost me <$500 per window. At this point in time, I will need to find another alternative until I can afford to dump $2000 for dual windows. A web site I have gone a lot to in the past has an interesting low cost solution for insulating your glass- Bubblewrap!!! check it out: http://www.builditsolar.com/Projects/Conservation/bubblewrap.htm This guy has some great ideas about a lot of stuff. A couple of days ago I was at Home Depot buying the reflectivix stuff- looks like I will take it back and try a bubblewrap alternative.