Every fall, your mailbox fills up with cheerful brochures promising free dental, vision, and groceries.
What those mailers rarely mention is who pays for all that generosity, and it isn't the insurance company's shareholders.
The two main paths for Medicare enrollees work in opposite directions.
Medicare Advantage (Part C) bundles your coverage into one plan, often with a $0 premium, and the insurer decides which doctors you see and what gets approved.
A Medicare Supplement (Medigap) pays the leftover bills from Original Medicare and lets you keep any doctor in the country who accepts Medicare.
The other is traditional coverage with fewer surprises.
The premium math is where people get tripped up.
Advantage plans can advertise zero dollars a month because the government pays the insurer a set amount per member.
Medigap Plan G, the most popular supplement, runs roughly $100 to $200 monthly depending on your age, gender, and state.
That's real money on a fixed income, and it's why the $0 pitch wins so many kitchen-table conversations.
But compare total costs, not just the sticker.
Original Medicare pays 80% of most covered services; you're on the hook for the other 20% with no annual ceiling unless you have a supplement or other coverage.
Advantage plans cap your yearly out-of-pocket spending, which sounds protective until you learn those limits can climb past $8,000 in-network for 2025, and higher still for out-of-network care.
A hospital stay, a cancer diagnosis, or a skilled nursing stay can push you toward that ceiling fast.
Then there's the fine print that decides your year.
Advantage plans use prior authorization, meaning a clerk or an algorithm can delay or deny care your doctor ordered.
A 2023 federal review found that some denials were later overturned on appeal, which tells you the first answer isn't always the right one.
Medigap plans don't require prior authorization for covered services, and there are no networks to check.
If you sign up during your six-month initial enrollment window, insurers generally must sell you a policy regardless of health history.
Miss that window, and in most states you can be rejected or charged more for diabetes, heart conditions, or past surgeries.
Advantage lets you switch back only under limited circumstances, which is why the advice "try Advantage first, switch later" can backfire badly.
There's also a quiet marketing machine at work.
Advantage plans are heavily advertised by brokers who earn commissions per enrollment, and some receive higher payouts for certain plans.
That doesn't make the plans bad, but it does mean the person explaining your options may not be neutral.
If you can afford the premium and want nationwide access without prior authorization, Medigap plus a standalone Part D drug plan is the more predictable route.
If the premium is out of reach, an Advantage plan with a low out-of-pocket maximum and your doctors already in network can be workable.
Check your medications against the plan's formulary, call your doctors to confirm they're in network, and read the annual notice of change every fall, because plans quietly alter copays and drug tiers.
The takeaway: "free" is a marketing word, not a financial plan.
Run your own numbers using last year's actual medical bills, and treat any broker's recommendation as a starting point rather than a verdict.
Final Thoughts
The right choice depends on your health, your budget, and your tolerance for paperwork, not on which envelope looks friendliest.