My folks were not educated just good with their $$$.
My Dad worked at the Engine Plant by layoffs in the early 80s he hadda enough time there "partial" pension or early retirement and saved up enough money to buy afew old houses cheap , fix em up and then rented them out.
Once that got going they aqquired many more houses started a buisness even incorporated & got certified by State accept "Rental Assistance" because take that ya get inspected & unit must meet the mark get government money.
Anyways they got Old sold all of the places back in the 1990s at probably a quarter what they are valued today but did very well for themselves at that time and retired started travelling even even flew to Hawaii a coupla times