Medicare is a federally funded and operated program designed for the elderly (age 65 and over) and certain disabled individuals. Medicare Part C, also known as Medicare Advantage, are health insurance plans offered by private insurance companies for coverage of Medicare eligible services. Private Fee-For-Service (PFFS) plans are a type of Medicare Advantage plan that allows an individual to go to any Medicare participating provider, as long as the provider is willing to accept the PFFS plan. This differs from HMO and PPO plans, which require that the individual go to certain approved in-network medical providers, even if other medical providers who accept Medicare are available in the area. But there are some disadvantages to a PFFS plan.