Most of the options here are Hof and Soju bars that are all pretty much the same - they offer beer by the truckload w2500 for 500ml and soju. Many of them will expect you to order food as well since this is Korean tradition. Just politely say "no thanks" and most will leave you with you beer. Those looking for cocktails have to go to a cocktail bar and these are priced very highly. Your best bet is to head to E-Mart and get a few bottles of cheap booze if you want liquor.