Places to Shop - Nonno 21

Nonno 21 is located near Nambu bus terminal a major transport hub in Seoul.

Their online store is www.nonno21.com

Like Hobby Plus I strongly suspect Nonno21 might be retail only. Certainly their website doesn't display magic very prominently. 

Contact Details
Phone number: 02-3465-0094
Korean Street address: 서울특별시 서초구 서초동 국제전자센터 9층

Places to Shop - Hobby Plus

Located very close to Nambu bus terminal Hobby Plus is registered with Wizards for tournament play but don't really have the space for it. 
I am under the impression they just sell sealed product.

Their online store is http//www.hobby-plus.co.kr

Contact Details
Phone number: 070-8614-4900
Email address: info@hobby-plus.co.kr
Korean street address: 서울특별시 서초구 서초동 국제전자센터 9층