Part A is Hospital Insurance and covers cost associated with confinement in a hospital or skilled nursing facility. (see Medicare Part A)

Medicare Advantage Plans are health plan options that are approved by Medicare but run by private companies. They are part of the Medicare Program, and sometimes called "Part C." When you join a Medicare Advantage Plan, you are still in Medicare. (see Medicare Part C) With Medicare Advantage Plans:

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: