Research the current exchange rate. Newspapers publish the rates, and you can find them easily online. If you exchanged currency when you arrived in the country, the exchange rate for cash purchases is printed on your receipt. For example, as of November, 2010, the exchange rate between the U.S. dollar and the Brazilian real is approximately 1.71, so a dollar will buy 1.71 reals.
Convert local prices to your home currency. Divide the stated price by the exchange rate to convert it to your home currency. A souvenir sweatshirt with a price tag of 50 reals, for example, costs about $29.25: 50 divided by 1.71 equals 29.24.
Convert your home currency to local money by multiplication to compare prices. If a hamburger at home costs $6.95, then a price of 12 reals (6.95 times 1.71 equals 11.88) is probably reasonable.
