How to buy gift cards to send to Korea from the U.s.

I am wondering if there is anyone here ever purchased gift cards and made payment from the US to send to Korea? I am struggling now, 'cause Korean e-commerce sites that I can search for like Gmarket, or Coupang all reject US cards.

I am sorry if this post goes to the wrong Category, 'cause Im not sure which is the most proper one for it.