Many Americans opt to enroll in Medicare Advantage (Part C), a program which allows you to enroll in private health insurance that offers both Medicare Part A and B benefits. Medicare Advantage plans are not supplemental insurance, but rather health insurance plans of their own. Medicare Advantage can also include prescription drug coverage in addition to vision, hearing, and dental. In most cases, you can join even if you have been diagnosed with a pre-existing condition, except for final stage renal disease. Advantage plans must follow guidelines established by Medicare but also vary in terms of costs and rules.