Concrete homes aren't expensive
The price you quoted for your home sounds about right and I'm sure someone could build a home for much less.
I helped out with the construction of ours, I ran the mud or salvage and we went through 4 teams before we found a two man crew that worked, a larger crew is needed in the beginning but after the floor and support pillars are poured you don't need more than 2 or 3 workers.
Lessons learned...buy the materials yourself and that includes the sand, blocks, bars cement bags, these guys alway's find a way to steal your supplies or up the costs.
Always be vigilant.