Sometimes a driver may ask for 100 baht. The higher price is usually asked in the late evening, early morning hours. Bartering the initial price asked is common practice, but don't undercut too much. The driver has to make a living. Tuk-tuk's are available 24 hours a day.
Common sense plays an important role when riding in a tuk-tuk.
Obviously don't stick arms, legs, or head outside the passenger area. Be aware of your surroundings, traffic in Thailand can be intense at the least. Keep a close eye on the driver late at night or early in the morning, they tend to work a lot of hours and have been known to doze off periodically while driving. They sometimes have had more to drink than the passengers. Sam lars are three-wheeled tricycles with a covered seat in the back that are powered by the individual driving them.