Taxi and tuk - tuk are two alternative ways to travel in Thailand, although tuk tuk is only useful for very short distances.
Here few tips it is worth for you to know.
I. When travelling with taxi make sure the fare counter is on.
II. If you are using taxi for medium / long distances ( not advisable, use train or bus instead) bargain a price before to start your travel.
III. Tuk tuk can be very expensive, don't use them if it is not necessary.
IV. Always bargain a price withh tuk tuk drivers before to get on the tuk tuk
V. The "right price" is usually at least half of the price initially asked by the tuk tuk driver.
VI. if you are going to stay in the same town / area for few days consider hiring a scooter as an alternative way of transport.