I think it really depends on what you choose as your living expenses...

If you like fruit and western food, it can become quite pricey.

An apple at E-mart can go for 5000won where at the market you can get is for 500 won.

Franxhise pizza can cost up to 35,000 won, but a california roll is only 1000 won and still gets you full. Ramyun is about 600 won, and they would get you just as full.