When I first came to Korea in 2003, the average starting wage for a public school teacher or hagwon teacher was around 2 million won. Today, it's much the same and some public school teachers are working for as little as 1.8 million, while the average hagwon starting wage has increased a bit to around 2.2 million. The potential for saving a considerable amount of money is still there, especially with the free airfare and housing, but it's much harder to live comfortably on 500 000 or 600 000 than it was back in the old days and I'd say the average expat probably spends between 800 000-1 million/month.
Unis are a whole different thing entirely because there are just so many more factors to consider beyond the base salary. Airfare and housing are often not included in the package, although places may offer key (deposit) money or a monthly housing allowance. The wage per hour has to be considered because the base hours can range from 9-18+ per week and vacation can range from 4 weeks to 20 weeks per year. And overtime opportunities are what can actually increase pay significantly and this actually matters a lot more than the actual base salary.
Here's an article from Expat Newswire with more details:
Looking for the big money? The Middle East is probably where it's at these days: