When considering switching Medicare plans, you will want to consider what the difference in costs may be. Original Medicare typically involves premiums, deductibles, and coinsurances as well as higher out-of-pocket costs. Medigap, however, can be paired with Original Medicare plans to reduce out-of-pocket costs and cover outstanding costs left over from deductibles, coinsurance, and copayments. Medicare Advantage plans work differently — more like HMO and PPO plans where you pay different premiums depending on the specific coverage you need, but have specific max out-of-pocket costs.