Daiso near Seongsu: Seongsu 2-ga Store (106 Seongdeokjeong-gil) and Ttukseom

Station Store (6 Achasan-ro), 10 am-10 pm, both within 1km of Seongsu Station. The 6-step adjustable tablet stand is ₩3,000 with 1.7K+ orders, handy for video calls. 6단 means six angle settings. Seongsu is full of cafes, so you can start working right after.