When we first got married we were poor and NO ONE built a home for US! We worked and saved and did without extras and bought our own little tiny first house back in 1975.
In 1975, we borrowed $2000 from my husband's father and purchased both sides of a little duplex for $18,000.00. We rehabbed it, at one point scrapping cat poop out of corners replacing flooring where it was too bad. We painted everything and put down new carpet, etc. etc.
We rented out the other side for enough to pay our mortgage and paid off my father in law in one year. From that and then a second duplex purchased with the GI bill, and another with FHA, we lived in and rehabbed property until today we own several rental properties. It's still a modest portfolio but will help us retire. We figure we can downsize through each property, two years in each, and avoid capital gains as we sell them off but we'll probably end up giving two or three of them to our children, or more likely, like our father in law did, we'll sell them to us and they'll pay us back.
In some places, it's almost impossible to buy a house though. That's why my wife and I bought an existing one that had all the things we needed. The time and extra money it would have taken to build a new one weren't worth it to us.