Money

The most common bills are the $1 (a "buck"), $5, $10, and $20 denominations. There are also $2 bills (seldom encountered), $50 bills, and $100 bills (the last two are usually not welcome as payment for small purchases).

Coins come in seven denominations: 1¢ (1 cent, or a penny); 5¢ (5 cents, or a nickel); 10¢ (10 cents, or a dime); 25¢ (25 cents, or a quarter); 50¢ (50 cents, or a half-dollar); the gold-colored Sacagawea and presidential coins, worth $1; and the rare silver dollar.

It's always advisable to bring money in a variety of forms on a vacation: a mix of cash, credit cards, and traveler's checks. You should also exchange enough petty cash to cover airport incidentals, tipping, and transportation to your hotel before you leave home, or withdraw money upon arrival at an airport ATM.

ATMs

Nationwide, the easiest and best way to get cash away from home is from an ATM (automated teller machine), sometimes referred to as a "cash machine" or "cashpoint." ATMs are everywhere in Hawaii -- at banks, supermarkets, Longs Drugs, and Honolulu International Airport, and in some resorts and shopping centers. The Cirrus (tel. 800/424-7787; www.mastercard.com) and PLUS (tel. 800/843-7587; www.visa.com) networks span the country; you can find them even in remote regions. Go to your bank card's website to find ATM locations at your destination. Be sure you know your daily withdrawal limit before you depart.

Note: Many banks impose a fee every time you use a card at another bank's ATM, and that fee is often higher for international transactions (up to $5 or more) than for domestic ones (where they're rarely more than $2). In addition, the bank from which you withdraw cash may charge its own fee. To compare banks' ATM fees within the U.S., use www.bankrate.com. Visitors from outside the U.S. should also find out whether their bank assesses a 1% to 3% fee on charges incurred abroad.

Credit Cards & Debit Cards

Credit cards are the most widely used form of payment in the United States: Visa (Barclaycard in Britain), MasterCard (Eurocard in Europe, Access in Britain, Chargex in Canada), American Express, Diners Club, and Discover. They also provide a convenient record of all your expenses and offer relatively good exchange rates. You can withdraw cash advances from your credit cards at banks or ATMs, but high fees make credit card cash advances a pricey way to get cash.

It's highly recommended that you travel with at least one major credit card. You must have a credit card to rent a car, and hotels and airlines usually require a credit card imprint as a deposit against expenses.

ATM cards with major credit card backing, known as "debit cards," are now a commonly acceptable form of payment in most stores and restaurants. Debit cards draw money directly from your checking account. Some stores enable you to receive cash back on your debit card purchases as well. The same is true at most U.S. post offices.

Why Oahu Is More Expensive

No, it's not your imagination -- Oahu is more expensive than the other Hawaiian Islands. That's the result of the Hawaii State Legislature passing a bill allowing the City and County of Honolulu (which is the entire island of Oahu) to add an additional .5% tax on to the state general excise tax of 4%. Everything you buy on Oahu will have this tax, and so will your hotel bill. The funds from this additional tax are earmarked for mass transit for Oahu.