Original Medicare Leaves You Exposed to Unlimited Costs — Consider Adding Coverage First

Original Medicare does not set an annual cap on what you pay out of pocket. You can limit that exposure with a Medigap policy such as Plan G or with a Medicare Advantage plan. If you go the Medigap route, it’s best to enroll during your six-month open enrollment period, when insurers cannot reject you or charge you more because of your health.

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Millions of people still have neither type of protection. KFF reported that in 2023, 3.5 million beneficiaries — 13% of those in traditional Medicare — had no supplemental coverage at all.

Without extra coverage, you generally pay 20% of the Medicare-approved amount for Part B services after meeting the $283 deductible. By our calculation, a year of $100,000 in outpatient cancer treatment can leave you with more than $20,000 in bills. Part A also carries a $1,736 hospital deductible in 2026, which can apply more than once in a year, along with daily charges for extended hospital and skilled nursing facility stays.

Your Medigap enrollment window begins during the first month you are 65 or older and enrolled in Part B, and it does not come around again. After that, insurers in most states may review your health, then deny coverage or raise your price unless you qualify for a guaranteed issue right, such as when your Medicare Advantage plan leaves your area.

There are two main ways to cap your costs:

• Medigap Plan G covers your share of Medicare-approved expenses except for the Part B deductible, while High-Deductible Plan G limits your exposure at $2,950 in 2026. Both require a monthly premium.
• A Medicare Advantage plan often has a lower monthly premium, but you could still owe as much as $9,250 for in-network care in 2026. KFF says the average limit is $5,421, and most enrollees are in plans that generally cover only in-network care except in emergencies.

To compare Medigap prices, start with Mutual of Omaha. AM Best gives Mutual of Omaha Insurance Company an A+ (Superior) rating. Its online quoting tool provides prices for Plan G and High-Deductible Plan G based on your ZIP code, birth date, and sex, without requiring contact information. On Sept. 23, 2026, the company quoted High-Deductible Plan G at $45.84 to $52.19 per month for a 65-year-old woman in Dallas (75201), Columbus (43215), and Phoenix (85004). Where available, couples may lower costs through a household discount, although the amount and eligibility rules vary by state.

Because Plan G offers the same benefits from every insurer, compare Mutual of Omaha’s quote with the Medicare.gov listings for your ZIP code before applying.

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