Option 1: Medicare Supplement insurance covers some or most of the coverage gaps in Medicare. On the plus side, your choice of doctors and hospitals is national in scope. On the downside, Medicare Supplement is expensive for the risk insured. That's because original Medicare leaves very little financial risk uncovered. (The exception is prescription drugs. You should buy a Medicare Part D prescription drug plan.) Option 2: Medicare Advantage Plans cover most or all of the Medicare gaps and also bundle extra coverage like prescriptions, dental and vision. A Medicare Advantage plan will cost you very little if anything beyond your Medicare Part B premium. Why? They collect a substantial monthly check from Medicare for taking care of you. The downside is that the Advantage Plan networks are limited in choices and geography. The Affordable Care Act has provisions that will cut payments to Medicare Advantage Plans and make it more difficult for them to offer extras or even stay in business.