Korean post office. But send it by boat, it's so much cheaper than airmail, it does however take awhile to get to its destination though. I shipped some stuff back last year and it took about 2 months, but only cost me 15000 won. Also, I recommend anything you are shipping to be put in plastic bags with a list of whats in each bag inside the box. Some of my boxes accidently got opened (due to rough handling on the boat) and I ended up with a random shoe and a few other odd things from someone else's package. If the boxes open, they just shove it in whatever box is closest unless there is a list.
