Medical coding is a big deal right now precisely for the reasons you indicated. The entry barriers are not as high as those required for becoming a doctor, nurse, or other medical practitioner, but the job is still in high demand because it is in the medical field. Medical coders, unlike other medical staff members I just mentioned, do not work directly with patients or administer treatments. But they do need to have a knowledge of physiology so that they can translate the business of a hospital or clinic into medical codes. These codes are used to streamline and simplify communications and make them objective. That way it is easier to send out medical bills, distribute supplies and personnel, and so on.
As to whether or not you should get a degree in the field, I would say that in the long run, the answer is yes. Whether or not you should get one immediately depends on the details of your situation. You say you do not have much time or money to spend on a degree right now. That may make a certificate a better option for the time being, and at the very least I highly recommend you go to school to get that. Certifications are required by more and more employers, and they can increase your salary.
A degree, whether it be an associate’s or bachelor’s degree, can also increase your income significantly. The difference between the wage for a medical coder just starting out with nothing more than a certificate and that of a coder starting out with a bachelor’s degree can be the difference between a salary that barely can pay the bills for one person and one which can comfortably support a small family.
This is why I highly suggest you pursue a degree in the field, whether now or later. If you start out with a certificate, you can begin getting work experience and setting aside money so you can go back to school later. You also may find an employer who is willing to help finance further education. Once you get a higher degree you have a much better shot at making a really good salary as a medical coder. You can find detailed information on this topic if you visit the website for the American Association of Professional Coders (AAPC).