If you are desperate for $20 and $200, that probably means you or your kids are hungry or need medication to stay alive. Your friends at Square are here to help. Square's peer-to-peer payment service, Cash App, is testing a new feature that offers loans between $20 and $200. You have four weeks to pay the loan back at 5% interest. If you miss the payment, you get a one week grace. After that, Square will add 1.25% interest every week. That turns out to be a 65% annual interest rate (fortunately non-compounding).