Created by Square, Cash App is first on our list for its user-friendly interface and flexible mobile payment options. When you want to send a contact money, you can do so using either your Cash App balance or a linked credit card, debit card, or bank account. In addition to sending and receiving money, you can also use Cash App to buy and sell Bitcoin or invest in stocks. One thing to note is that Cash App does charge a transaction fee if you decide to use your credit card for payments, making it a more costly option than some others on this list.