During the day you can get cheap and delicious meals at the market or at the restaurant in the Muang Thong Hotel. In this hotel it's also possible to have breakfast eggs, toast, butter, & jam. There is a vegetarian restaurant on the main road if you walk south from the bus station. At night it is worth trying the restaurants on the riverside. Tuesdays and Thursdays there is a night market 500m south of the bus station on the main road. Many guidebooks recommend Duang as a good place to eat. However as a tourist you will probably pay more than Thais. And Malaysians may have to pay even more than other tourists.
