A Medigap, or Medicare Supplement policy is an insurance policy 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. Medigap policies are sold by private companies, and can help pay for some of the costs that Original Medicare doesn't, like copayments, coinsurance, and deductibles.
Medicare Supplement Plans are accepted by over 95% of all doctors/providers in America. Referrals are not required. Many people love the freedom of choice for your medical provider, predictability of costs, and very low rate increase history with most carriers.
Medicare Advantage Plans are Guaranteed Issue, have No Pre-existing Limitations and usually offer co-pays for Doctor, Hospital and RX costs. Premiums are often $0 per month.