Daiso Hongdae 2nd Store (182 Yanghwa-ro) is near Hongik Univ.

Station, and Hongik Univ. Station Store (25 Hongik-ro) is inside the shopping area; both open 10 am-10 pm. The croissant charm is ₩2,000 with 96 reviews (4.9). Small and light, so a few as gifts won't fill your suitcase. Both are walkable from the station, so you can visit both.