A Medigap plan, also known as Medicare Supplement Insurance, is an extra insurance policy sold by private health insurance companies to help pay for some of the health care costs that Original Medicare doesn't cover. These costs may include copayments, coinsurance, and deductibles. Some Medigap plans also offer coverage for services that Original Medicare doesn't cover, such as medical care when you travel outside the U.S. It's important to note that Medigap plans are different from Medicare Advantage plans, as they only supplement Original Medicare benefits and do not include prescription drug coverage. To be eligible for a Medigap plan, you must have Medicare Part A and Part B, and you will need to pay a monthly premium to the private insurance company in addition to the monthly Part B premium you pay to Medicare. It's also worth mentioning that a Medigap plan only covers one person, so if both you and your spouse want Medigap coverage, you will need to buy separate policies