The most convenient form of money in Mexico is a major international credit card or debit card. Credit cards can also be used to obtain cash from ATMs in Mexico, and are accepted for payment by most airlines, car rental companies, travel agents, many upper mid-range and top-end hotels, and some restaurants and shops. However, it's probably a good idea to have more than one credit card as acceptance of cards is erratic - American Express in particular is not accepted by some Mexican businesses. Visa, Amex or MasterCard stickers on a door or window in Mexico do not necessarily mean that these cards will be accepted for payment there. As a backup, it's wise to take some travelers checks and a little cash. US dollars are still the most easily exchangeable foreign currency in Mexico.
In heavily touristed areas such as Acapulco, CancÃ