These sleek, prefab buildings can add an office or spare bedroom to your backyard from $33,000 — take a look

Aux Box, a prefab builder based in British Columbia, Canada, creates prefab offices and ADUs that are shipped as far as Ontario or California.

https://www.businessinsider.com/tiny-homes-prefab-adu-auxbox-backyard-office-cabin-pricing-models-2023-12