The national currency is the Kuwaiti dinar KD, KWD.
The dinar is divided into 1000 fils. Notes are available in denominations of KD 20, 10, 5, 1, Â½ and Â¼, while 100, 50, 20, 10 and 5 fils coins are also available. While notes have Latin numerals on one side, the coins are entirely in Arabic.
Notes issued before 1994, many of which were stolen during the Iraqi occupation, are not considered legal tender. You're unlikely to see these in Kuwait the designs are clearly different, but unscrupulous dealers elsewhere have been known to try to pass them off. See the Central Bank of Kuwait (http://www.cbk.gov.kw/www...) for pictures.
Exchanging money can be difficult and exchanging travelers cheques even more so. Stick to ATMs, which are ubiquitous and work fine. Higher-end establishments accept credit cards.
Although Kuwait is a tax haven 0% VAT and 0% income tax It would be hard to manage on under US$80 per day, and you can very easily spend US$200 just on an ordinary hotel room.
Tipping is generally not necessary. A 12% service charge is tacked onto your bill in expensive hotels and restaurants, but if you want some of the money to actually go to the staff, leave a little extra.
Prices on common expenses January 2009:
Burger combo meal: KD 1.25 - 1.75 Hardee's
Hotel breakfast: KD 5.00 - 6.25 depending on how new the hotel is!
Bunch of Bananas ~1 kg: 450 fils
Single-tall latte with an add-shot at Starbucks: KD 1.25
Falafel sandwhich in Hawally: 100 fils
Petrol prices are one of the cheapest in the world and most of the time are cheaper than water, literally!