President Jimmy Carter was brought up on a peanut farm, which is fairly common knowledge. Yet the young Carter was also an incredibly enterprising young man. Prior to leaving home to be educated at Annapolis and the Naval Academy, Carter gained much experience in the way of business and investing.
After saving money from various ventures such as transporting produce, selling hamburgers and hotdogs and collecting scrap iron, young Carter took his father's advice about investing his savings in bales of cotton. He waited four years to sell his purchase of five bales, which made him such a profit that he was able to purchase five rental properties. The real estate investment not only made money for Carter well into WWII, but it also made him a landlord at only 13 years of age.
Read about the odd jobs of nine other presidents — from executioner to janitor — here.