that is interesting about the hay bales.. I have seen stuff on TV where homes are built with hay bales and they are very warm inside during cold winters with little heat..
wonder how much it cost to get hay bales.. I seem to remember seeing them in my area for like 3 to 4 bucks a bale or so. I guess you would need 10-15 to more or less. I bet you can get them your self and save a bit of cash. Most of the time that is a straw hay and not really for animal eating more for bedding and such.
hope to make it to amazon when we go fulltime in 5 or so years.