The premiums for Medicare Part B will remain flat in 2014 and seniors have saved $8.3 billion on Part D prescriptions since the Affordable Care Act was enacted in 2010, the Department of Health and Human Services announced Monday. Medicare Part B covers medically necessary services, as well as preventive services. Premiums for Medicare Part B will stay at $104.90 a month for 2014, the same as in 2013, according to the Center for Medicare Services. Premiums have either decreased or stayed the same for the past three years. The deductible will also remain at $147.