Had a friend who.lived in a place like that in Sunnyvale.
90 sq feet: http://www.youtube.com/watch?v=JZSdrtEqcHU
450 sq feet: http://www.youtube.com/watch?v=8RbxkrmuQ5E
Living in a garbage truck: http://www.youtube.com/watch?v=hNxzBkz6a_g&feature=related
I agree with a previous poster that big cities used to have rooming houses where a single person could live at reasonable rates. Those are pretty much gone. Besides, no one has a gun to your head.