Medicare itself has four parts. Part A (hospital insurance) and Part B (health insurance) come standard in every Original Medicare Plan. Part C is called Medicare Advantage, and it's an alternative to a standard Medicare Plan that offers some additional benefits like prescription drug coverage. Stand-alone prescription drug plans, or Part D, cover prescription drugs for those who want to keep their Original Medicare plans. And then there is Medigap.
Medicare Supplement Insurance plans are private health insurance that can help you pay for the "gaps" in your traditional Medicare policy – such as copayments at a doctor's office, coinsurance at skilled nursing facilities and out-of-pocket hospital costs not covered by Medicare Part A. There are 10 different types of Medicare Supplement Insurance plans, each designated by a letter of the alphabet (you can find details about all 10 plans at Medicare.gov). In most states, the benefits are the same no matter what insurance company you purchase the plan from, though each plan covers different things. Premium prices for each of the 10 Medigap plans varies depending on the benefits offered, and the premiums are separate from your regular Medicare premiums.
To be eligible for a Medicare Supplement Insurance plan, you must already have Medicare parts A and B. The most comprehensive Medicare Supplement Insurance plan is Plan F, which covers all available benefits. Plan C, which covers everything except excess health insurance costs, and Plan F are the most popular plans.
The advantage of a Medicare Supplement Insurance plan is that you will have a larger network of providers from which to choose. If you have a health condition, a Medicare Supplement Insurance plan may also provide better ways to pay for medical expenses. If you can afford to spend a bit more, a Medicare Supplement Insurance plan may be a wiser choice. It may save you a lot of money in the long run if you need extensive medical services or treatments.