Money

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.

Compared with much of America, Montana and Wyoming are a bargain. Especially when you get away from the national parks and major resorts, you'll find that lodging and dining is relatively inexpensive. However, you might need to budget a bit more for transportation here, mainly because distances between destinations are so great. In Montana, Canadian currency is usually accepted at the current conversion rate, especially near the border.

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." 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'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 their cards 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.

Traveler's Checks

Though credit cards and debit cards are more often used, traveler's checks are still widely accepted in the U.S. Foreign visitors should make sure that traveler's checks are denominated in U.S. dollars; foreign-currency checks are often difficult to exchange.

You can buy traveler's checks at most banks. Most are offered in denominations of $20, $50, $100, $500, and sometimes $1,000. Generally, you'll pay a service charge ranging from 1% to 4%.

The most popular traveler's checks are offered by American Express (tel. 800/807-6233; 800/221-7282 for card holders -- this number accepts collect calls, offers service in several foreign languages, and exempts Amex gold and platinum cardholders from the 1% fee); Visa (tel. 800/732-1322) -- AAA members can obtain Visa checks for a $9.95 fee (for checks up to $1,500) at most AAA offices or by calling tel. 866/339-3378; and MasterCard (tel. 800/223-9920).

Be sure to keep a copy of the traveler's checks serial numbers separate from your checks in the event that they are stolen or lost. You'll get a refund faster if you know the numbers.