To be honest, a common problem you might have is that some places only do an order for two. That could be wayyyyyyy too much if you just want a taste.

For example, I found this place on a Korean blog. While I've yet to try, it actually looks quite good. Or at least they're good food bloggers. It's near Seoul University Station on Line 2, which may not be the most ideal.

http://leeve.tistory.com/m/post/1015