Mother's $10-per-square-foot (or Less!) Earth-sheltered House
https://www.motherearthnews.com/sustainable-living/green-homes/earth-sheltered-home-zmaz83ndzale/
https://www.motherearthnews.com/sustainable-living/green-homes/earth-sheltered-home-part-two/
https://www.motherearthnews.com/homesteading-and-livestock/self-sufficient-homestead-zmaz85mazraw/
Obviously will cost more than $10 per square foot in todays economy.
Monolithic domes are structures usually inflated as a dome. Rebar supports are added, then insulation and concrete are sprayed on . The results is a very strong structure that didn't take that much time and can be affordable.
The company is based out of Texas and has lots of stories about the dome homes surviving tornadoes and hurricanes with little to no damage.
Micheal Reynolds developed a house built out of trash and earth. It has a total system designed to shelter it's occupants, provide food, water, and power. It is labor intensive, and, not as cheap as you would imagine, but it is a great structure.
https://earthshipbiotecture.com/
With all the global shipping, there are standardized modal containers that are sometimes discarded after one or a few uses. The big deal is the strong ridged frame that allows the containers to be stacked. The sides and top are not really structurally strong and should be reinforced. If breached for windows and doors, they will need to be framed. Containers may be contaminated with mold and chemicals. Requiring extensive cleaning. The containers are fairly affordable, just need to be transported in most cases.
Sizes include
8' X 20', 8' x 40', high cube, and some are refrigerator or freezer containers, so may be insulated.