every thing and anything depends on the IO that you see on arrival. They decide they want anything and you dont have it they can refuse you entry. Likelyhood due to your ticket is doubtful they would stop you.
To be safe you can always buy a cheap on forward ticket for about $12
nope did not cost anything to transfer it to them. Sorry but I gave my aussie experience. Your post didnt say a country or a currency.
I would look into a registered exchange company and get quotes. They killed wise when I used them and it was much more than required than the 800,000baht