To avoid this, travelers can familiarize themselves with a country's currency before leaving home. One way to do this is by acquiring some of the bills and coins you'll be using and memorizing their worth. Credit cards and debit cards are widely regarded as the tools that will get you the best exchange rates in Europe. If you can afford to pay up front, using a debit card is fine. But if you're going to have to run up some bills to pay for the trip, taking a credit card or two is an obvious choice, said Jeanne Kramer, the director of market research for Fodor's Travel Publications, a New York publisher of travel guides.
Credit cards represent a line of credit from the bank that issues the card.
Debit cards, sometimes called check cards, are a pipeline directly into your checking account. If you take a credit card, make sure your credit limit is high enough to get you through the trip. If you need the limit increased, call your credit card issuer and request it. That's something you'll want to do before your trip, not from a phone booth in the Puerta del Sol in Madrid. Even if you don't need to increase your limit, you may want to tell your credit card issuer that you're going to Europe.