I just went to the Lotte Duty Free Shop in South Korea a few days ago to do some shopping. At that time, I paid with a Guangfa credit card. Not only was there no foreign exchange transaction service fee, but I also got a full discount when I used the Guangfa VISA card. When you spend over 100 US dollars, you will get an instant discount of 15,000 won, and it is said that you can get up to 150,000 won!