Some of the shopping malls of my recommendation is as follows
1. WesternDome and La Festa in Goyang City
Huge shooping malls in Ilsan Goynag, The 2 shopping malls are connected in a short distance, The food court in Western Dome is one the 2nd floor and it is consisted of Korea, Chinese, Japanes, Thai and other Western food. Price for food ranges from 5,000 Korean won to 8,000 Korean won in most of the cases.
2. Preminum Outlet in Paju
It is located near the Unification Observatory in Paju. It has a small mini train and beautiful garden, It reminds me of the US shopping mall
3. . Lotte mall in Kimpo International Airport
It is located on the bottom part of the Kimpo International airport. You may save some time since it is connected with Incheon International Airport by airport train. Price is rather high that the other places.