Many people find that carrying lots of one-dollar bills is helpful, primarily for use as tips. Only non-U.S. credit cards are accepted. Banks and hotels accept Travelers Checks from all countries, but not American Express. There are rumors that banks and hotels now accept American Express travelers cheques because they can be cleared through Canadian banks, but to be safe, don't use them. It doesn't matter what your citizenship is.
Some people have bank accounts in England, Mexico, Canada, Israel, etc.
Even if they are U.S. citizens, they can use these cards. Mostly any bank and stores in shopping malls in major cities will accept credit cards. Banks and hotels. Banks are less friendly, but you'll pay less. Food Money Shelter Travel Health Social Giving Children Other Shelter.