And another thing: You can bring in as much money as you want, only you have to declare it at the customs. But no worry, Customs and You will fill out a form and there is no tax or anything like it involved. Keep the form in case you want to take a larger amount out. Up to the amount brought in (shown on the form) you get no problem, even if it is over the normal limit.
If you have Thai money left and intend to come back, then you will best open an account at a Thai bank and leave your money there. Also you get a Debit Card / ATM Card, which is a good thing to have in Thaiand.
IF you want to buy Thai currency abroad you get a very bad rate, maybe 10 or 20 % less than in Thailand. And why would you want to do that? You can exchange at the airport Suvarnaphum at the bottom level, where you also have the access to the Aairport Raillink. There on the left side are moneychangers, that offer better rates than banks.
They want to entice you to use an agent for processing your visa extension. That way they split the spoils between them, which you pay for in the form of the service.
Like it or not, at least the agent will get your stuff done in short time.
That were monkeys in cameo, dressed up like humanns?
Anyway, a passport has become expensive and there should be no waste of space in it. Even with an extended passport (48 instead of 36 pages) my passport never lasts the full 10 years.