"ever been in a hay bale / stucco building?"
Some nearby friends built a porch addition onto their ranch house using straw bales.
About the only good thing that I could see about it, was the great insulation value and the fact that they already had the straw bales.
The amount of labor involved is atrocious! Of course, just stacking the bales doesn't take much time, but then they had to painstakingly apply the chicken wire and stucco (two layers, inside and out) plus a bunch of hardware to tie the bales together (little cables, clamps, turnbuckles, etc). My two daughters helped them with mixing and applying the stucco. The only advantage is that all that labor is pretty much totally unskilled - you don't have to be able to even read a tape measure or swing a hammer.
I figure I could have built that addition with lumber and plywood in a weekend.
The thing that most folks don't seem to realize is that the wall materials are going to only be about ten percent of the total cost: foundation, roof, windows, doors, plumbing, fiixtures, wiring, etc are going to be about the same either way. Just like a yacht - the accomodations cost more than the hull. So even if you save half on the cost of the walls, that is only 5% of the total cost.
I went through this years ago with some folks who wanted me to cut and stack logs on their land so they could build a cabin. Their trees were mostly worthless for that purpose, being short, branchy, and tapered a lot. But they thought they could save so much money using trees from their own land. I finally got out of that one when I discovered that they could not even show me their exact property lines
I'd love to have a stone house (a little castle tower, maybe...?) but hopefully we will live in this place (frame/wood siding) for the rest of our lives. I'm getting too old and worn out to build now. But we did build a little 3-sided log shelter for our horses using wind and ice damaged trees from our land. All it cost was a few spikes and chainsaw gas. We even scrounged the metal for the roof (but we had to buy some screws).
If I had an easy and cheap source for some flat rocks, just for fun I would like to build a "beehive" shieling (cottage) on our land.