Next month I'll be visiting South Korea for the first time, and this will probably be my only trip to Korea in a long time. So I am planning on buying some additional learning material while I am there, because this will probably be much cheaper than ordering them online. Which bookstores are the best for buying these kinds of book? In Seoul I'll be staying in Gangnam and apparently there's a Kyobo Bookstore nearby. Would this store be a good choice for buying learning material? Or are there bookstores with a wider selection of books on Korean?
I also want to buy Hangul stickers for my computer keyboard, similar to these. Where would I be able to find these? The ones on Amazon are pretty cheap, but the shipping costs make them really expensive for me...