I've had good luck with a 4* in Seoul for the last couple of years (2-3 times per year). My bids range from $75-90/night on average. However, for my next trip (11/6-10) I had to up it to $110 about 2 weeks ago to get the reservation. In Gangnam I've always gotten the Renaissance Seoul. This is very nice hotel. Extras are a package of internet and breakfast for around KR35,000 / day (maybe 40,000) or about $35-40. The breakfast is good for business travelers although it is a little excessive. There is a Starbucks on the corner near the hotel. I don't recall how much the internet is per night on its own but I do remember it being expensive ($25/day?). I believe the G20 or APEC is in Seoul in late October/November making it harder to get rooms right now. Good luck.
