Overnight trains and the 20-baht rides

The sleeper trains from Bangkok to Chiang Mai and to the south are comfortable, cheap, and a night's accommodation saved; book second-class air-conditioned berths a week or two ahead on the State Railway site. In Bangkok, the public river boats and the regular city buses cost next to nothing. Across the country, the local songthaew pickup trucks run fixed routes for a small flat fare; ask the price before you get in.