If you're 65 or older, the mail pile on your kitchen counter is probably stuffed with promises.
One envelope says you'll get dental, vision, and a gym membership for a $0 monthly premium.
Another warns that you'll face unlimited hospital bills if you don't act now.
Both are selling something real, and both are leaving out the fine print that decides whether you save money or get buried in paperwork.
The two main paths are Medicare Advantage (Part C) and Medicare Supplement plans, often called Medigap.
They work in opposite ways, and the gap between them can run into five figures a year depending on your health and your doctors.
Medicare Advantage replaces Original Medicare.
Private insurers run it, often bundling drug coverage and extras like hearing aids.
The trade-off is networks: you generally must use in-network doctors, and you may need referrals and prior authorizations before care gets approved.
Premiums can be low or even $0, but copays and out-of-pocket maximums still apply.
You keep Original Medicare and buy a private policy that covers most of what Medicare leaves behind, like the 20% coinsurance on doctor visits.
There are no networks, so you can see almost any provider nationwide.
The catch is price: premiums commonly run $100 to $250 or more per month, and you still need a separate Part D drug plan.
The monthly math is where people trip up.
A $0 Advantage premium sounds unbeatable next to a $180 Medigap bill.
But a single hospital stay or a round of cancer treatment can trigger thousands in Advantage copays, while Medigap picks up most of that tab.
There's also a deadline that quietly traps people.
In most states, you get a one-time Medigap open enrollment window that starts when you're 65 and enrolled in Part B.
Miss it, and insurers can charge you more or deny you outright based on your health history.
Advantage plans let you switch annually, but moving back to Medigap later is not guaranteed.
You can try Advantage and switch plans every fall.
You cannot always buy your way back into Medigap once medical issues pile up.
Which one fits depends on your situation.
If you travel a lot, have serious health conditions, or want to see specialists without referrals, Medigap's predictability may be worth the premium.
If you're healthy, live on a tight budget, and are fine staying in a local network, Advantage can keep costs low for years.
Check whether your doctors and hospital are in the plan's network.
Add up the worst-case annual out-of-pocket maximum, not just the premium.
And confirm your drug list is covered, because a formulary change in January can wreck a good deal.
Every state has a SHIP program, staffed by counselors who don't sell insurance.
They'll walk you through the comparison for nothing, which beats trusting a cold call.
Don't let a flashy $0 premium decide this for you.
The cheapest plan today can be the most expensive one after a diagnosis, and the window to change your mind may already be closing.
Final Thoughts
Read the summary of benefits, run the worst-case numbers, and talk to a neutral counselor before the deadline passes.