While some cryptocurrencies, including bitcoin, are available for purchase with U.S. dollars, others require that you pay with bitcoin or another cryptocurrency. To buy cryptocurrencies, you’ll need a “wallet,” an online app that can hold your currency. Generally, you create an account on an exchange, and then you can transfer real money to buy cryptocurrencies such as Bitcoin or Ethereum. Coinbase and Bitpay are two popular cryptocurrency trading exchanges where you can create both a wallet and buy and sell bitcoin and other cryptocurrencies.