Here’s what 8 baht buys you.
There are many different classes of bus that you can take in Bangkok; air conditioned, rapid bus, and these bad boys, which I lovingly call “wooden floors”. I can’t even begin (literally) to explain how this works, except to say you get on, and attendant (sometimes, eventually) comes to you, and you pay up. They give change.
It cost us 8 baht to go the 15 kilometers from our guesthouse to the Science Center and Planetarium today. Mind you , it took two full hours in mind0-numbing traffic. Children are free on buses (apparently).
Coming back was a bit quicker; 37 baht for 7 stops on the skytrain and then 12 baht for AC bus. Total return travel time, 37 minutes.
There really is no rhyme or reason.