Other cards on the market typically charge a 3 % foreign transaction fee on transactions made in foreign currencies. (creditcards.get.com)
Some banks may charge a transaction fee on every transaction you make while some may limit the number of transactions you can make before they charge fees. (finder.com)
For example, if you don't put the exactly right fee on a transaction it can get stuck, where it won't get confirmed by the network. (hypepotamus.com)