There is no monthly premium for Medicare Part A (hospital insurance) if you've paid Medicare taxes for at least 10 years — otherwise, it will cost $274 to $499 per month. Part B (doctor insurance) has a $170.10 monthly premium and the cost will vary for Part D (prescription drug coverage). Deductibles and coinsurance payments still apply but may be covered if you purchase Medigap coverage, which pays for some costs not covered under an Original Medicare plan. If you purchase a Medicare Advantage Plan (health coverage that follows Medicare guidelines sold by private companies), Parts A, B and D are often bundled into a single plan and the costs will vary per provider.