No Cash, No Checks, No Problem Peer-to-peer payment apps are one of the newest ways to send money. Share | Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content The Power of Compound Interest Learn how to harness the power of compound interest for your investments. U.S. Personal Savings Rate What can be learned from the savings rate? Doubling Your Money This calculator demonstrates the power of compound interest.