Since at least biblical times, money changers have been gouging foreign visitors exchanging their currency for local shekels. Fortunately, if you’re going outside the U.S. this summer, you can avoid most of the gouge. Unless you’re a currency speculator, you’ll almost always lose a little in exchanging your dollars for whatever, but you can keep those losses to no more than around 1 percent: The actual cost of exchanging currency is the 1 percent or so that the international Visa, MasterCard, or American Express networks charge to do the exchange job.
But many credit and debit card issuers add their own foreign charges and fees for doing nothing—they gouge because they can—running the cost up to 5 percent or even more.
Retail foreign exchange desks can use a combination of lousy rates and fees to run your cost up to 10 percent or more. These days, using the right plastic can limit your loss to that 1 percent. That means both a credit card and a debit card…