Where are you allowed to sleep for free in the US? You could perhaps get a wilderness permit and live in a national park for a time, but I'm not sure what the maximum period of validity is on them. Cities will cite you under anti-camping rules. There isn't really a frontier to go to where a person can live off the land, at least so far as I'm aware.
People who do not find the system of "I have to work because I have to have money because I have to pay rent/own a home because I have to have somewhere to sleep" satisfactory no longer have a frontier to which they can escape. This is worrying if you like the idea of preserving liberty, and especially worrying if (as this article suggest) the whole monetary system on which our civilization is built rests on weak foundations.
At least prison's still more or less free.
http://www.alternet.org/civil-liberties/us-laws-criminalizin...