There's a heckuva lot more than that. In the vast majority of cities, the land isn't worth a fraction of everything else involved. You can't just pay your 10k

There's a heckuva lot more than that. In the vast majority of cities, the land isn't worth a fraction of everything else involved. You can't just pay your 10k(or even 100k) for a plot, 125k for a prefab, then call it a day. If you could, house values would absolutely plummet. You've got the permits, the foundation, driveway, utilities, and the whole issue of paying someone to put the parts together, to name a few.