Remember you pay for Medicare Part A premium while you work through your taxes, once you start using your Medicare Part B, you pay the part B premium at that time.
Currently for 2011 the standard Medicare Part B premium is 115.40 per month.
Due to the fact that there was not a Social Security cost of living adjustment for 2011, those who were already enrolled in Medicare Part B in 2010, they will pay the same Medicare Part B premium they did in 2010 as long as their income for an individual is less than $85,000 and $170,000 for a couple.
Since 2007, individuals who file their income taxes with an income greater than $85,000 and couples over $170,000 will pay a monthly premium based on a tiered level according to their income. This tier affects less than 5% according to a social security report.