The Malaysian currency is the ringgit, informally known as the dollar (the "$" symbol can be seen on older notes) and abbreviated RM or MYR, is divided into 100 sen. There are coins of 5, 10, 20, and 50 sen as well as bills of RM1, 2 (rare), 5, 10, 50 and 100. 5 sen coins are mainly given as change in large establishments and supermarkets, peddlers and street vendors might be reluctant to accept them. Note that the Singapore and Brunei dollars are also known as ringgit in Malay, so when near border areas you might want to check to be sure which currency they are quoting the price in.
Ringgits are freely convertible. Foreign currencies are not generally accepted, although you might get away with exchanging some Euros or US dollars even in more remote areas, but do expect a lot of stares and some persuasion. The major exception is Singapore dollars, which are accepted by KTMB and toll roads, but at a highly unfavorable 1:1 exchange rate (an anomaly dating back to when the ringgit was interchangeable with the Singapore dollar, prior to the 1970s).
Banks and airports are not the best places to exchange money if it is not urgent. Licensed money changers in major shopping malls often have the best rates - be sure to say the amount you wish to exchange and ask for the 'best quote' as rates displayed on the board are often negotiable, especially for larger amounts.
ATMs are widely available in cities, but do stock up on cash if heading out into the smaller islands or the jungle. Credit cards can be used in most shops, restaurants and hotels, although skimming can be a problem in dodgier outlets.
Banks in Malaysia, especially those in major towns and cities, have staff who are trained to handle international transactions. For any enquiries and transactions, get a number, sit down and wait for your turn to be served. (There is no need to queue while you wait in air-conditioned comfort!)
Banks are open Monday to Friday from 9.30AM to 4PM and selected banks are open on Saturday from 9.30AM to 11.30AM except on the first and third Saturdays of each month. In the states of Kedah, Kelantan and Terengganu, they are open Saturday to Wednesday from 9.30AM to 4PM and Thursday from 9.30AM to 11.30AM.
Most visitors will find Malaysia quite cheap, although it is noticeably more expensive than neighbouring Thailand and Indonesia. You can live in hostel dorms and feast on hawker food for less than RM50 per day, but you'll wish to double this for comfort, particularly if travelling in more expensive East Malaysia. Kuala Lumpur is also generally more expensive than the rest of the country. At the other end of the spectrum, luxury hotels and air fares are comparatively affordable, with even the fanciest 5-star hotels costing less than RM400/night.
Tipping is not customary in Malaysia. However, hotel porters and taxi drivers will appreciate a small tip if you have been provided with exemplary service. Most expensive restaurants, bars and hotels may indicate prices in the form of RM19+ , meaning that sales tax (5%) and service charge (10%) will be added to the bill. Hotel tax of 5% may also be added to this.
Kuala Lumpur is a shopping mecca for clothes, electronics, computer goods and much more, with very competitive prices by any standard. Traditional Malaysian fabrics (batik) are a popular souvenir. The cheapest place to easily buy ethnic souvenirs (especially wood-based) is in Kuching, East Malaysia, and the most expensive place is in the major, posh KL shopping centres.
In general shops open from 10.30AM until 9.30PM (or 10PM) in the large cities. They open and close for business earlier in the smaller towns and rural areas.
If you buy too much shopping in Malaysia - quite easy to do - surface postage rates are very reasonable. Excess luggage at the airport is still high, but its not as high as others. Check first with your airline.