For credit cards specifically, such as the American Express card we are currently interested in, this fee has been set at 3. As one of the oldest operating Bitcoin exchange services ever, CEX. Bitcongress is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon. You can exchange cryptocurrencies at any time, and the process is completed almost instantly. To give you a little background, while buying coins with credit or debit cards used to be a complicated process in the past, technological modifications along with sincere efforts from companies like Coinbase and CoinMama have ensured that the entire process is now much more streamlined and functions pretty smoothly.