There is a small Home plus close to my new place. Home plus is partly owned by British super giant Tesco, which means you can find some Western things that the other big Korean markets (Emart, Lotte) do not have.
This neighborhood, however, is rather Korean, especially as I was just in HBC (the most western part of Korea) for the last 2 months. So you can find things like Sweet Pumpkin/Yam tea.
And my favorite. Korean “Black Beer Stout” which is decidedly average. But this particular promotion comes with a a free toothbrush and mini-toothpaste. Perhaps to erase the bland taste as quickly as possible?