Comment Don't forget about the Open Source alternatives (Score 1) 203
There's the Hexayurt Project, which is basically an updated geodesic dome and can be built up to 450 square feet for each module using only hand tools and a screw gun and the Wikihouse which is a fablab style design which relies on a router.
A typical deployment for a family home would be three hexayurts made out of polyiso foam and then sprayed with ferrocement. Cost is probably around $1500 for that approach, but that's first-world costs. With hand-plaster rather than sprayed ferrocement, I think a developing world unit could well hit $1000.
And, of course, a simple plywood hexayurt for disaster relief is $100 per family, half the price of a disaster relief tent.