It always seemed to me that if ADUs were selling for $50,000 or less, there would be lots of interest. Literally the first one I ran into (below) at the Tiny Fest was priced at $50,000, and people were standing in line to experience this 8.5 ft x 30 ft home with kitchen and full bath (seen in right window).
https://backporchhomes.lpages.co/back-porch-homes-companion-gallery/
This one was tall enough that it had two lofts:
https://www.tinymountainhouses.com/
For those who want to do it themselves, these guys will sell you the kit for $63,000. The vaulted ceiling added some extra luxury:
This was my favorite granny flat because of the porch. The upgraded version costs $65,000:
This was the deal of the day. For $15,000 you get the building with full bath and the trailer:
Here’s my tour of the homes: