While and food and clothes are still easier to come by comparatively, a durable roof over head is still a luxury for many.
If you type ‘low cost’ in Google search pane, the most options for related search query are pertains to houses and housing.
One innovative low cost option is to use discarded old vehicles as part of a mud-house. The body completes the roof and some windows of the mud-house. While small vehicles cannot suffice for a family, they surely make a good outpost or a single person shelter.
Himalayan Institute of Alternatives, Ladakh has been pioneer in this concept.