When you join a Medicare Prescription Plan, you pay a monthly premium. The average plan premium varies depending on the plan you choose. This premium will be in addition to any premiums you already pay for Medicare Part A and Part B coverage. There are minimum standards required by Medicare for all plans, but the plan providers have the flexibility to have different premiums, deductibles, and co-payments. Competitive providers may choose to offer better plans for consumers, but may not provide less than the standard.
For the standard plan, the deductible is subject to change annually. After you pay the deductible, coverage is broken down into three additional levels. How you progress through these levels depends on the costs of your medications.
For more information, see: Centers for Medicare & Medicaid Services, U.S. Department of Health and Human Services, Medicare & You (2015), http://www.medicare.gov/Publications/Pubs/pdf/10050.pdf (last visited May 28, 2015).