You can buy and sell bitcoin with your Cash App. What is Bitcoin? Bitcoin is the first and most well known example of a new kind of money called a “cryptocurrency. Cash App has an easy on-boarding process and allows USD to bitcoin purchasing without a fee via your debit card or balance within the app. Square is the first. Cash App. Square's (SQ) Cash App allows people to easily send money to each other, but it has also become a way to buy stocks, pay.