When Tanis and I visited Seoul we saw lots of young women in traditional hanboks, which gave our tour an extra sense of history. Above I’ve added a video of two Korean vloggers who explain that if you come in traditional dress, you get in free.
Another tip: As we exited the subway we passed a group of high school students volunteering to take tourists around Gyeongbuk Palace. I’m so glad we accepted the offer. Jin, whose English was quite polished, gave tours once a month to further his English and deepen his understanding of history. The tour was more than just your run of the mill “Look to the left, look to the right.” Whoever devised the tour included lots of Q and A so it’s very interactive and exceeded my expectations. It’s absolutely free.