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-14-fed-funds-rate How open market operations effect the rate at which banks lend to each other overnight. More free lessons at: http://www.khanacademy.org/video?v=IniG1KkPS2c