There are two Comesum outlets. One inside the station at the central waiting area connecting PF# 1,2,3,4,5,6 without dine-in facility and one outside near the unreserved ticket counter which is sort of a restaurant. Surprisingly, the former is decently priced but the restaurant is overpriced. Maybe because of the difference in menu served or whatever.
Another thing, the McD is tax free. Do turns out to be cheap.