Frommer's lists prices in U.S. dollars or local currency, both of which are widely accepted. Rates fluctuate, so before departing, consult a currency exchange website such as www.oanda.com/convert/classic to check up-to-the-minute rates.
Laos in general is still a cheap place to travel, though you can easily spend a great deal on accommodations and food in Luang Prabang, where many hotel rooms will set you back $200 a night and $30 or $40 a meal is average. Yet this all changes once you are in the countryside and smaller towns, where you can get a room for as little as $3. If you pay $15 then you will enjoy relative luxury for that town. The same is true of dining, and Vientiane is one of the best places in Asia to dine well for little money. For $10, you are in gourmet territory.
The main bank in Laos is the Bank Pour Le Commerce Extérieur Lao. They exchange cash and traveler's checks and issue U.S. dollars in all the major towns. They also advance money on MasterCard and Visa and charge 3% commission. The Joint Development Bank also changes cash and traveler's checks. Both banks now have ATMs in Vientiane, Luang Prabang, Pakse, Savannahkhet, and Tha Khek. ATMs are springing up at a rapid rate, and many accept both Visa and MasterCard. They are not particularly useful if drawing money from a foreign account, since they only issue Lao kip with a daily limit in the region of 700,000 kip and the transaction charges are very high. Bank exchange booths are far better. They are rapid and can issue U.S. dollars as well as Lao kip. In Luang Prabang, many travel agents also change money and traveler's checks as well as advancing cash on a credit card.
The official currency is the Lao kip. Notes come in denominations of 500, 1,000, 2,000, 5,000, 10,000, 20,000, and 50,000 (the endless zeros can give you a real headache after a while). There are no coins. Both the Thai baht and the U.S. dollar are also accepted and are used for larger transactions. If you are carrying larger amounts of cash, then it is best to carry dollars or baht. Also bear in mind that the kip is non-exchangeable outside Laos.
Credit cards are accepted by larger hotels, more expensive restaurants, and boutiques. In general, though, their use is restricted and Laos is very much a cash economy.