If you're turning 65 this year, or already on Medicare, you've probably been buried in mailers promising free dental, free groceries, and a $0 monthly premium.
Those ads are almost always selling Medicare Advantage.
What they rarely mention is the other option: a Medicare Supplement plan, also called Medigap.
The two paths work in completely different ways, and picking the wrong one can cost you thousands of dollars a year.
Medicare Advantage (Part C) is run by private insurers that contract with the government.
You keep paying your Part B premium, and in exchange you get one card that covers hospital, doctor, and usually drug coverage.
Many plans charge a $0 premium on top of that.
The catch is networks and prior authorizations.
You generally have to stay in-network, and the plan can require approval before covering procedures.
It also caps your yearly out-of-pocket costs, but that cap can run several thousand dollars.
You keep original Medicare as your coverage, and the supplement plan picks up most or all of the gaps: deductibles, coinsurance, and the 20% that Medicare doesn't pay.
You can see any doctor in the country who accepts Medicare, and there are no networks or referrals.
A Plan G Medigap policy can run $120 to $200 a month or more depending on your age, gender,zip code, and tobacco use.
The monthly math is where people get tripped up.
Advantage looks cheaper on paper, often dramatically so.
But one hospital stay with a few days in a skilled nursing facility can wipe out a year of premium savings.
Medigap buyers are essentially pre-paying for predictability.
There's another factor people miss: Medigap plans are standardized by letter.
A Plan G is identical in coverage no matter which insurer sells it, so you can shop purely on price and customer service.
Advantage plans are not standardized, so comparing them means digging through drug formularies, provider directories, and star ratings.
If you have a chronic condition, see specialists, or travel a lot, Medigap tends to be the safer bet.
If you're healthy, take few prescriptions, and want the lowest possible monthly cost, Advantage can work well — as long as you understand you may face prior authorizations and network limits.
One warning worth repeating: in most states, you can be turned down for Medigap after your initial enrollment window if you have health issues.
That window is generally six months starting when you first sign up for Part B.
Miss it and you may be locked out of the option entirely.
Also be careful with ads that promise extra benefits like dental, vision, or grocery cards.
Those are real on many Advantage plans, but they're often capped at a few hundred dollars a year and shouldn't drive a decision worth thousands.
My take: treat this as a risk decision, not a discount decision.
If you can afford Medigap, the predictability is usually worth it, and switching later is much harder than choosing right the first time.
Final Thoughts
Talk to a licensed broker who isn't paid by only one carrier, and run your actual drug list before you commit.