Original Medicare includes Medicare Part A (Hospital Insurance) and Medicare Part B (Medical Insurance). You pay for services as you get them. When you get services, you’ll pay a deductible at the start of each year, and you usually pay 20% of the cost of the Medicare-approved service, called coinsurance. If you want drug coverage, you can add a separate drug plan (Part D). 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 copayments, coinsurance, and deductibles. Some Medigap policies also cover services that Original Medicare doesn't cover, like emergency medical care when you travel outside the U.S.