Getting around town is pretty simple by foot but if you are looking for other forms of transport, bicycles approximately 50 baht per day and motor bikes approximately 150 baht per day can be rented by the day from one of the guest houses listed here, or from the lovely Thai Tiny Tim speaks good English, on the left just past Mae Sot general hospital. You must wear a helmet supplied as the police do fine people even foreigners!. You have to leave your passport for bond and fill up with petrol when you return it. Cars and 4 wheel drives can be hired from several places around town e.g. Well Driving, close to Casa Mia. Be very careful as the driving in Thailand can at best be described as unconventional and at worst, downright dangerous.
Taxis come in the form of motor bike or tuk tuk, usually found near the Burmese market and outside Tesco drivers sit around with special licenced number jackets. Obviously, prices depend on distance and passengers, but as a rough guide, 50 - 100 baht will get you to most places around the town.