The Centers for Medicare and Medicaid Services (CMS) has announced that the standard 2013 Medicare Part B (Medical) premium will be $104.90 per month. Some people pay a higher premium.
The Centers for Medicare & Medicaid Services is the agency in charge of the Medicare program, even though you apply for Medicare at Social Security.
More information about Medicare changes for 2013 is posted at http://blog.medicare.gov/2012/11/16/2013-medicare-update/. You can reach this same information through www.medicare.gov.