This is another mobile app where you can buy and sell Bitcoin with no fees. The key in the wallet is used in accessing Bitcoin address. While the exchange offers great real-time transactions, it does charge higher fees than some others on this list at 5. There is no mobile app, but the website is very high quality. I’ve been buying bitcoins for more than three years. Because Bitcoin transactions are irreversible, it’s risky for a merchant to sell bitcoins for CC payments.