After leaving office, President Truman lived on just $113 per month.

President Harry S. Truman never had it easy. He had only served as vice president for 85 days when President Roosevelt died. After that, Truman took over as president and had to lead the country through World War II.

After his presidency, Truman returned to his home in Independence, Missouri. Despite past precedent, Truman decided not to join the corporate world. He believed that accepting the money would lessen the integrity of the nation's highest office. However, he had no personal savings and only his old army pension to live off of—$112.56 per month.

(Source)