In most cases, if you choose to buy Part A, you must also have Medicare Part B (Medical Insurance) and pay monthly premiums for both.
Part B costs:
You pay a premium each month for Medicare Part B (Medical Insurance). Most people will pay the standard premium amount. However, if your modified adjusted gross income as reported on your IRS tax return from 2 years ago is above a certain amount, you may pay an Income Related Monthly Adjustment Amount (IRMAA). IRMAA is an extra charge added to your premium.
How much does Part B cost?
Most people pay the Part B premium of $134.00 each month, however consult the chart below if you have an individual income over $85,000 or joint income over $170,000.