Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/economics-finance-domain/core-finance/money-and-banking/banking-and-money/v/banking-3-fractional-reserve-banking Fractional reserve banking and the multiplier effect. Introduction to the money supply. More free lessons at: http://www.khanacademy.org/video?v=nH2-37rTA8U