Ive actually did some market research into this. Turnkey container houses, built out on trailers (with enough facade to make it look good, but since its not a permanent dwelling you don't have to pay property tax on it).
The big issue that I found is that people aren't actually interested in cheap houses, they just want something that is affordable at a discount but will grow in value, just like their parents did.
There is a lot of nuances to the issues I want to address, but you seem to be mistaking my fundamental goals. I don't want to "change" the housing market, or even build cheap houses.
If the market says the cheapest house in a market is $250k then that is my budget ceiling for equipment and materials, while all labor is provided by myself and any like-minded individuals in a similarly absurd situation. The 'difference' I would be making is the invisible-to-the-market value created by putting the cost of labor and any expected profits back into making the home a standing testament to human engineering.
There would be no marketing, no sales pitches, no brand or company associated with the construction of these homes. Simply going from place to place doing my best to make an insignificant difference at a societal scale and a silent but substantial difference to the families who eventually occupy those homes both now and in a hundred years.
Not the person you replied to, but given the logistics and local nature of relevant laws in construction there most likely isn't going to be a "recognized brand" that will give you a fair and reasonable price for anything except a traditional manufactured home that is governed under HUD manufactured housing program. (https://www.hud.gov/program_offices/housing/rmra/mhs)
Your best bet is to either find a company near you that specializes in tiny-homes and ask for a quote on a custom home that is built on a trailer (that you or the company sources) or simply buy an RV / Camper.
At the end of the day though if you're looking for something that is 'ultra affordable' then you will want to build it yourself. For that scenario I can point you at a number of resources that would help you along that path, just email or text me using the contact info in my profile.
Uncharted Tiny Homes is the only one that builds small homes, but I was looking into tapping some college resources (they have competitions on sustainable container houses) and some talent there in terms of what it takes to build one out.
You can get shipping containers pretty cheap, and the trailer doesn't even have to have wheels for it to be considered not a permanent residence.
The short of building out a house is basically you cut holes in the container for all the inteface to the outside world, do insulation on the inside, facade on the outside, run all wire/plumbing stuff in cut channels in the insulation, then build out the walls and furniture from treated wood. A lot of the existing RV stuff (shower, retractable beds, e.t.c) can be reused.
The big issue that I found is that people aren't actually interested in cheap houses, they just want something that is affordable at a discount but will grow in value, just like their parents did.