ATM's are accessible and recommended in many countries. Debit cards can be used but are not always accessible in some countries. Traveler's checks are not recommended since not every place takes them and the rate of exchange is not the best. You should not carry too much cash at one time. Only take what you think you might need for a few days. Credit cards are recommended but not all places accept them (public transportation, etc.). Typically Visa is accepted in other countries. Your individual program will provide information about your country.