Shop up a storm at Starfield COEX Mall. With plenty of places to give your credit card a workout, you can easily while away the day hunting for bargains.
This shopper's paradise is in Gangnam-gu, but Starfield COEX Mall of course isn't the only thing to see in this corner of the world. If you're looking for more sights, Dongdaemun History and Culture Park is worth a detour as well.