Dont bother with paying for the breakfast;
Its not very good and its rather expensive.
Third, if theres a large tour bus or two they turn it into a buffet and dont check who has paid. And if you prepay its $6 usd (180 baht) but 150 baht (about $5 usd) if you pay same day.
But for the price you're better off ordering from GrabFood for about the same price.
Or spend 60 baht ($2 usd) on street food or mini-market.