As in the rest of the United States, credit cards are widely accepted. You'll have little to no difficulty with Visa or MasterCard. American Express and Discover are also accepted but not quite as universally, especially in smaller towns. You may very well have problems if you present a JCB card for payment as most Idahoans have neither seen nor heard of them.
Travelers checks are likely to warrant confused looks if presented outside of tourist areas, and personal checks rarely accepted without prior arrangements.
If paying in cash, US dollars are the way to go, although Canadian dollars may be accepted by some merchants in the extreme north near the border. Occasionally Canadian coins become intermingled with US change and may be accepted at face value, or even given as change back to you. This can and does occur even in southern Idaho. Even so, don't be put off if they're refused. Paper currency, however, is all US dollars; if you're south of Sandpoint, don't even try anything else.
Sales tax in Idaho is currently 6 percent, which is assessed on most goods including food. The tax is collected at the time of sale, regardless of whether you're from Idaho or not. Some municipalities mainly in tourist areas, as well as Nez Perce County in north central Idaho also assess a local sales tax in addition to the state tax. There are also taxes included in lodging costs at hotels, motels and campgrounds. Some services are not subject to sales tax.
Native American tribes in Idaho are currently exempt from charging sales taxes on tobacco products. The Nez Perce Tribe charges an alternative tobacco tax to fund scholarships on the tribe's reservation near Lewiston, while the Shoshone Bannock Tribes on the Fort Hall Reservation near Pocatello don't charge tobacco sales taxes at all.
Tipping your server or bartender is considered good etiquette at sit-down restaurants and bars, but is generally not expected elsewhere. Even so many Idahoans consider tipping optional - especially in rural areas - so good tips tend to be appreciated by waitstaff much more so than in other places.
Idaho souvenirs almost always follow one of two themes: outdoor topics such as hunting, camping, fishing and skiing, or potatoes. The latter can be particularly kitschy, with characters such as "Darth Tater" and "Spudbob Starchpants" available for purchase at just about any convenience store or truck stop.
