My friend took us to his favorite place to buy socks on Friday night. He's just a random vendor on the street in Dongdaemun, but the socks are crazy cheap. 10 pairs for 6,000 won.
My friend picked up lots of socks to bring home to England with him in a few weeks, and we got a few for ourselves too. Our friend tried on one pair when we got back to my place and realized that there were actually feet on his socks. We all agreed these were the coolest socks imaginable. If you find this vendor in Dongdaemun, be sure to buy some foot socks.