Which Online Class can you Take to Learn Medical Billing?

I would recommend that you enroll in a community college or technical school as it is generally the cheapest way to get training in medical billing and coding.

Remember,  

Regardless of their background, you will eventually have to appear and pass exams, such as CCS-P or CPC, which are nationally recognized and accepted in the U.S.. These are some of the few conditions established that the employers (hospitals and health care) considered the industry standard. The first is given by the AHIMA and the second is a credential of AAPC.

The CPC exam is an objective  

(multiple choice or true / false) and requires that you get at least 70% to pass. As with any test, it helps if you have prior experience or course of preparation.

The subjects studied 
 
To become certified CPC include radiology, pathology, anatomy, ICD-9-CM coding concepts, medicine, medical terminology and more.