I think most frugal people are born that way...
it has always pained me to spend money on trivial things.
I now pay cash for cars...I pay cash for houses
all because when I was in my 20’s and 30’s I saved rather than spent.....didn’t have to take a class...didn’t need someone to tell me how. It all came nauturally
It’s amazing the difference between starting to save in your 20s as opposed to your 30s, you could literally spend everything you make in your 50s, and wind up with the same amount of money at age 65, as someone who waited until their 30s to start saving.