Here is the cost of living by state: https://www.consumeraffairs.com/homeowners/states-with-lowes...
Some interesting states are West Virginia.
Cost of living is hard to calculate and I don’t know the best source. This one might be better: https://www.epi.org/resources/budget/budget-map/
Idk if the fertility rate is factored into the cost of living calculator … if it is then I guess the measure isn’t relevant.