The local currency is the Cambodian Riel (KHR). There are no coins in circulation. The money starts with notes of 100 riel, followed by 200, 500, 1000, 2000, 5000, 10,000, 20,000, 50,000 and 100,000. For a euro you will receive 5,309 riel (April 2012).
While you are in Phnom Penh and Siem Reap you can pay by credit card in some places like the best hotels and restaurants. It is also convenient to have (undamaged) notes of 1, 5 and 10 US Dollars. Cambodia in recent years has become a Dollar driven economy. The Cambodians round up Dollar amounts for tourists to whole Dollars, so make sure that you pay for little things in Riel. If you're not careful you will end up paying for everything in Dollars (although sometimes the change in Riel is returned). Travellers cheques (in U.S. Dollars) are accepted by most banks. There are few banks that will pay cash on your credit card. In Phnom Penh and Siem Reap you can withdraw U.S. Dollars from the ATMs.
Banks are open Monday to Friday opened in Cambodia from 7.00 to 14.30. Sometimes there is a lunch break (sometime between 12.00 and 14.00). A single bank in Phnom Penh is open on Saturday until 12.00. For the current exchange rates: www.oanda.com.
The allowance recommended by us is a minimum amount for your meals, drinks, optional excursions, entrance fees, local airport taxes and gratuities. The amount you actually spend will depend a great deal on your own habits and so therefore souvenirs are not included in this suggestion.