ISA Student Protection Act of 2019 This bill provides for income-share agreements whereby a student agrees to pay a percentage of future income, for a specified period of time, in exchange for funds to pay for educational expenses. The bill places caps on the percentage of a student's future income that may go towards repayment, provides income minimums under which the required payment is zero, and establishes limitations on the length of these agreements. The bill provides for the treatment of these agreements under various laws, including tax, securities, and consumer finance laws.