Jang Won is my go-to restaurant for All You Can Eat KBBQ. You can get AYCE pork belly (or SamGyupSal) for the mere price of 15 dollars!
The quality of the meat is decent, but not spectacular. But hey, remember: 15 dollars! What I like most about this place is the quality of their service. Whenever you ask for more meat or veggies, they give it to you post-haste. They respond quickly once you call for them, and they even throw in free bottles of beer or a bottle of Soju if your party exceeds three people.
I'd definitely recommend this place, especially if you're on a student's budget (which I unfortunately am :( ). I'll definitely be back again in the near future.