Here we explain Win tips to win in Thailand lotto by Bangkok: 06-01-2017
Winning tickets can be redeemed for their prize at any Provincial Office of the Comptroller General’s Department (CGD). There is one of these in every province (3 in Bangkok). The tax is 0.5% of winnings. It is possible to redeem at shops though the fee is higher, about 2% is a typical price to negotiate too.
Note: for reason that you have two identical tickets for every draw the prizes above are always doubled in Thai lotto. The only one that is not is the main 20 million and 30 million jackpots.