Cash App Support , Cash App Toll Free , Cash App Helper , Cash App Customer Care , Cash App Customer Service , Cash App Customer SupportOne of the largest cryptocurrency exchanges in the U.S., Coinbase is a place to buy, sell and hold digital currencies like bitcoin and ether. Now that cryptocurrency has gone more mainstream, there are several ways to buy and sell coins on your own, whether it be via Venmo, Cash App or a trading app like Robinhood.