A while back I did some research related to this, and while I wouldn't want to get into the uninhabitable house part of it, there do appear to be habitable and in fairly good condition 3BD size houses in
very rural areas for sale in some small midwest towns in the USA for around $40-50k. If you go look at some small towns in southern IL and set the zillow max price to 50-60k you'll see them.
At the very lowest end of the scale I found habitable houses in the 20-30k range in KS, OK and that area in small farming towns that have seen significant post-1960s exodus and population decline.
If you have the budget to build your own custom house and do something like an off grid solar setup, there's plenty of places in rural eastern WA state where you can buy 20 or 40 acres for $1k per acre.