The unit of currency in El Salvador is the U.S. dollar. The country made the switch from its native colón in 2001, and colónes have been phased out since 2004. Small-town tiendas rarely have change for a $20, so get small bills whenever you can. ATMs, known as cajeros automáticos, can be found in all major cities but are hard to come by in rural towns. Even when a smaller town has an ATM, it may not accept your card -- stock up on cash when you can.
Bank machines accept most major card networks, such as Cirrus, PLUS, Visa, and MasterCard. I've had the best luck with a PLUS card at Scotiabank ATMs. Credit cards are accepted mainly only in the larger hotels, restaurants, and shops. Sometimes, you get lucky in the most unexpected places, but generally, small shops or restaurants in villages are solo efectivo, or cash only. Those that accept credit cards usually take American Express, Diners Club, Visa, and MasterCard.
You can just about forget about traveler's checks. Almost no one outside of large San Salvador hotels accepts these anymore. If you feel more comfortable carrying traveler's checks, you can exchange them for currency at most banks or American Express offices.
The cost of basics in El Salvador varies wildly, depending on where you are. A good general rule of thumb puts San Salvador prices largely on par with those in the United States. You'll spend $6 or more for long cab rides and $5.50 for most fast-food purchases. Outside of San Salvador, however, all costs are considerably lower. A 10- to 15-minute taxi ride in La Palma is $3 and pupusas (the national dish) cost 25¢ each in smaller towns. San Salvador's finer restaurants and hotels -- though much more expensive than those in the rest of the country -- are also considerably cheaper than comparable places in the United States or the U.K.
Money Talk -- The widely used local slang for a quarter is a "cora."
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.