Every fall, your mailbox fills up with glossy promises: $0 premiums, dental, vision, and a free gym membership.
What those mailers leave out is the part where you can end up owing thousands before your coverage kicks in.
That's the fundamental divide between Medicare Advantage and Medicare Supplement plans, and it's the rare financial decision where the cheaper option can quietly become the more expensive one.
Medicare Advantage (Part C) replaces original Medicare with a private insurer's network.
Premiums often look tiny, sometimes zero beyond your Part B payment.
The trade-off is cost-sharing: copays for visits, coinsurance for hospital stays, and an annual out-of-pocket maximum that in 2025 can run as high as $9,350 for in-network care, according to KFF.
There's also a separate, sometimes unlimited cap for out-of-network care.
Medicare Supplement plans, often called Medigap, work differently.
You keep original Medicare and buy a policy that covers most of the gaps: deductibles, coinsurance, and copays.
Premiums are higher and rise with age, but your out-of-pocket costs are far more predictable, and there are no networks.
One important detail: Medigap plans sold today don't cover prescription drugs, so you'd need a separate Part D plan.
And a 2020 law closed the loophole that once let some Advantage plans bill you without limit for certain services.
If you enroll in Medicare Advantage when you first become eligible, you can usually switch to a Medigap plan later, but insurers in most states can then charge you more or reject you outright based on your health history.
In other words, the decision you make at 65 can lock in your options for the next 20 years.
Only a handful of states, including New York and Connecticut, offer stronger protections.
Advantage plans are lucrative, and the federal government pays them a set amount per enrollee, which is why the marketing budget is enormous.
Brokers pushing one plan over another often earn different commissions depending on what they sell you.
The honest answer is that "better" depends on your situation.
If you're healthy, take few medications, and want low premiums, Advantage can work fine.
If you have chronic conditions, travel often, or simply can't stomach a surprise bill, the predictability of a supplement may be worth the higher monthly cost.
Before you decide, check whether your doctors are in the network, add up your actual drug costs, and look up the plan's star rating and complaint data on Medicare's own plan finder.
Do the math with real numbers, not the ones on the flyer. **Our take:** The "$0 premium" pitch is a marketing decision, not a financial one, and the cost just moves somewhere you can't see it.
Final Thoughts
Run your own numbers, and treat any salesperson who won't discuss the out-of-pocket maximum as someone selling you something, not helping you buy it.