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.
