Thanks for all the replies - even the most awkward things get answered here.

I eventually booked an earlier flight into ICN (cheaper business fare), arriving before noon, then heading into to the city (City Air Terminal). From there, I will make a trip to a Lotte or similar - the hotel may have recommendations in close vicinity as well.

Yes, I do not want to haggle, but just go into a store and buy it fix price.

Thank you again!