Part B is Medical Insurance and covers physicians services, outpatient care, test, and supplies. (see Medicare Part B)

Medigap is Medicare Supplement Insurance that helps fill "gaps" in Original Medicare and is sold by private companies. Original Medicare pays for much, but not all, of the cost for covered health care services and supplies. A Medicare Supplement Insurance (Medigap) policy can help pay some of the remaining health care costs, like:

Why Do You Need Health Insurance?

Today, health care costs are high, and getting higher. Who will pay your bills if you have a serious accident or a major illness? You buy health insurance for the same reason you buy other kinds of insurance, to protect yourself financially. With health insurance, you protect yourself and your family in case you need medical care that could be very expensive. You can't predict what your medical bills will be. In a good year, your costs may be low. But if you become ill, your bills could be very high. If you have insurance, many of your costs are covered by a third-party payer, not by you. A third-party payer can be an insurance company or, in some cases, it can be your employer.