There are Jihwaja, Tosokchon Samgyetang, Hwangsaengga kalguksu. Or you can go to the traditional markets in Seoul to try a variety of dishes at cheap prices https://www.tripadvisor.com/Restaurant_Review-g294197-d1918214-Reviews-Hwangsaengga_Kalguksu-Seoul.html https://www.tripadvisor.com/Restaurant_Review-g294197-d1174982-Reviews-Tosokchon_Samgyetang-Seoul.html https://www.tripadvisor.com/Restaurant_Review-g294197-d10257443-Reviews-Jihwaja-Seoul.html