CryptoPostage – The Best Platform for Buying Shipping Labels Online Cryptocurrencies are a new form of digital currencies. They can be used for online purchases, and in some cases offline transactions as well. In order to use cryptocurrencies, you need to have a cryptocurrency wallet that stores your private keys and public address. You will also need to get a cryptocurrency exchange account if you want to trade fiat currency for crypto or vice versa. There are many reasons why someone would want to buy with cryptocurrencies, but the most popular one is privacy.