Foreign transaction fees and exchange rates can eat up your costs and cause you to spend more money than you planned. If the merchant chooses to bill you in dollars instead, he could conceivably choose any exchange rate he wants. Keep in mind that you will usually pay transaction fees, delivery fees and an exchange rate margin to a bank. Foreign transaction fees typically show up on your billing statement as separate charges. Consider blending several payment options, such as carrying cash with you and having prepaid and credit cards along with you as well.