|Uni Job Without a Masters Degree|
In my book,How to Get a University Job in South Korea: The English Teaching Job of Your Dreams I mention what you can do if you want to teach at a university with only a bachelor's degree. While really difficult, it is not entirely impossible to work your way into a uni job if you plan on staying in Korea for the long-term.
The best way to do it would be to take a job like this university language instructor position where you only need a bachelor's degree plus a year of experience, which is calculated at various rates, but essentially you'd be able to get it with 2.5 years of experience teaching at a public school or hagwon.
Then, hang on to that job for a few years, with 4 being ideal and you could potentially compete for many of the better university jobs out there. Or, just stay for 2 years and spend that time doing a master's degree in which case the world would be your oyster.