I am assuming you do not have
enough forest products on your host farm for a WOFATI or cordwood home, so I say the following.
I am not sure about permitting as the rules are very lax where I live, but if you check out this
thread, you can see how I built a 30 x 48 foot barn for $4450.
webpage
Now granted that is a barn, but if you look at the way it was framed, you can see it uses 1/3 the building material and that is a substantial savings whether you buy it or produce it from a forest as I did. But while that is a barn, I made an insulated lambing shed with the same 4 feet on center framing by placing non-load bearing strapping (1 x 3 boards) vertically so that I could
staple 2 foot insulation between the studs.
For good looking, cheap and functional walls, I used cedar shingles. ON THE INSIDE? Yep, and it is very cheap, and here is why. By stapling cheap lathes between the studs, they not only hold in the insulation, on 9 inch centers they allow cedar shingles to be stapled up. Normally shingles are stapled on in 5 inch high rows, but because it is inside and there is no weather to shed, they can be spaced at 9 inches, giving you some serious coverage for very little money.
Now my foundation was
concrete because it was animal housing, but you could reduce costs substantially by making a grade beam around your home, making it out of earthcrete instead of concrete, borrowing or renting a cement mixer. You could produce a
COB floor in between those grade beams, stone (as I did in my foyer) or any manner of locally available building materials. If you are so inclined the floor could be earthcrete as well using your borrowed, rented or small purchased cement mixer to do any of that.
For a roof you would have to go with steel, but it is VERY cheap, at less than a dollar a square foot, and it allows you to save 1/3 of your building materials as I mentioned before. With a shed roof (ugly I know, but simple), you would save money and have a functional home still.
This is not a complete list of the possibilities, but gives you an idea that a fairly normal house could be built far more inexpensively with no one knowing the difference, nor being an unsafe house to live in. And by the way, here a stick built home can be built more inexpensively than a mobile home or manufactured house can be obtained. Knocking off some of the extras and redundancies of building only lowers the cost.