From 1908 to 1942, you could buy houses through Sears catalogs. Sears sold about 70,000 of them throughout the US and Canada, and you could pick from 370 different styles. The cheapest models were about $360 (in early 1900’s dollars).
Although Sears houses haven’t been sold for well over 80 years, some people in modern times still build homes based on the old Sears plans, since they used fairly standard materials and many models were designed to be easily constructed by the homeowner.
Here is an ad for a large, 10 room model which sold for $6500, and an actual example of one,
It really isn’t. Somebody handy and resourceful, working a single living wage job for 40 hours per week could probably do it in their spare time back then in under 6 months. Pre-cut and fitted. I wonder what the percentage was on buyer-built vs hired assembly.