Medical coding certificate vs. degree?

So I was searching on my schools website for classes. I saw they have a medical coding and billing certificate . It only had I think it was just six or seven classes. It said graduates from the program could apply for jobs and medical coders and billers. Well I looked up the salary for a medical coder and its 30,000-45,000. It seems way way wayyyy too good to be true since six classes only takes like a semester and a half. Anyway, is there some sort of catch? I heard the classes weren't hard.Help meee thanks !