I would assume cost of living would include things like sending your children to school and so on, or going out on a fun weekend. If it does not, then I am sore

I would assume cost of living would include things like sending your children to school and so on, or going out on a fun weekend. If it does not, then I am sorely mistaken as what "cost of living" is. As for investing money back, I'd assume you would have some kind of an investment account (for future, retirement or even your child's college fund) that would provide the same returns no matter where you are.