Every fall, millions of Americans get buried in glossy mailers promising free dental, free groceries, and a $0 monthly premium.
But the gap between what Medicare Advantage advertises and what it actually costs you at the doctor's office is where the real money hides — and the insurance industry is counting on you not noticing until it's too late.
Traditional Medicare (Parts A and B) pays roughly 80% of covered costs.
A Medigap supplement picks up most of the rest, so your out-of-pocket exposure stays predictable.
Medicare Advantage, by contrast, is a private plan that replaces the government's payment structure entirely.
It often bundles in extras like vision and hearing — but it also controls which doctors you see and how much each visit costs through copays, networks, and prior authorizations.
The premium math is where people get tricked.
A Medigap plan might run $150 to $250 a month on top of your Part B premium, depending on your age, state, and health at signup.
But lower premiums don't mean lower costs — they mean costs moved somewhere else.
A hospital stay under Advantage can trigger daily copays that add up fast, and there's no annual cap on the traditional side until you hit catastrophic limits.
Advantage plans use provider networks, and if your cardiologist drops out mid-year, you're the one scrambling.
Supplements don't work that way — if a provider accepts Medicare, they generally accept you.
That flexibility is exactly why Medigap can't be bought cheaply, and why insurers lobby hard to keep people in Advantage instead.
The catch that traps people: Medigap enrollment is largely guaranteed only during a six-month window when you first sign up for Part B at 65.
Miss it, and in most states an insurer can charge you more or reject you outright based on your health history.
Switch from Advantage back to a supplement later, and you may be medically underwritten.
Insurers earn higher margins on Advantage plans through federal payments and cost controls, which is why marketing budgets for them dwarf anything you'll see promoting supplements.
The slick ads aren't neutral advice — they're sales.
Compare total worst-case annual costs, not monthly premiums.
Check whether your doctors are in-network.
Read the formulary for your prescriptions.
And if you're healthy and can afford the supplement now, understand that locking in that flexibility early may matter more than saving $100 a month today.
Our take: the $0 premium is a marketing number, not a medical plan.
Run your own real numbers for hospital stays, specialists, and drugs before you trust a mailer.
Final Thoughts
The cheapest sticker price is rarely the cheapest year.