The Sprint ETF is figures out through 'Progressive Reduction'. The amount you will pay depends on when you started the contract and the date you're finishing. It starts at $200 and reduces from there to the date you're canceling. At the link is a chart for you to use.
http://shop.sprint.com/en/services/termination_fee/early_termination_fee.shtml?ECID=vanity:etf