If it's a book you want, I would recommend Survival Korean by Stephen Revere.
Most textbooks will start you off learning the high-formal version of Korean. While this is useful to know, you won't hear it very often in daily life. I started off learning that way, and it seemed a huge waste of time to me; wasn't very useful.
Stephen Revere's book would have been awesome if I had been able to find it when I first started learning. I found it years later, when I was well beyond beginner, but I can easily see how great it would have been at the time. He's the only foreigner in Korea who is allowed to teach Korean to Korean students, and he's the host of a Korean-learning as well.
In short, he knows Korean inside and out, and he did it all from a learner's perspective, which is far better than most of the books written by Korean colleges, because those were written by Koreans from a teacher's perspective.