it's been a year but in the past i found nrticn booked on oz or nh to be a very affordable route, $100-150 return. and this is booked 2-3 weeks advance.
Lol I haven't seen that, ever. Last time I did a RT to NRT it was 300+.
NH would probably be cheaper but they don't fly to ICN. I guess I could fly via GMP but I don't have as many options for the airport bus to GMP from where I live.