Medicare includes: (2014)

Part	Description	Cost/ mo
Part A	covers hospital inpatient care, some types of home health care, hospice care, and care in skilled nursing facilities.	free
Part B	covers doctor services, outpatient hospital care, preventive care, and some types of home health care.	$105
Part D	covers prescription drugs.	$40

Medicare does not cover all of your medical expenses.
Medicare Parts A and B do not cover all of your health-care expenses. For example, you'll still pay a $1,184 deductible for the first 60 days of a hospital stay, and 20 percent of the cost of Part B services such as doctor visits, outpatient treatments, and laboratory tests.
There are basically two ways to handle the difference.

• Medigap or Supplemental insurance. Medicare pays their piece directly and Medigap insurance pays the difference.
  You still must enroll in Medicare Part A and B.
  Any doctor who accepts Medicare must accept Medigap.

  There are three pricing models.

  • Community-rated (also called no-age rated). The same premium is charged to everyone, regardless of age. Medigap experts say these plans are the least expensive over time, though not necessarily when you first purchase them.
  • Issue-age-rated. The premium is based on your age when you buy the policy. It won't go up as you age, but will increase due to cost inflation.
  • Attained-age rated. The premium starts low but goes up as you get older. Over time, this type of policy is the most expensive.
  Medigap plans come in 10 government standardized policies, lettered A, B and C, all the way up to N. Each Plan A has the same features, each Plan B has the same features, and so on. See details below.
• Medicare managed care plans or Medicare Advantage Plans. - They cover everything; billing Medicare themselves.
• Two options HMO and PPO. Limited to doctors that are in network.
  In general, in an HMO it is very difficult to get care out of network.
  In a PPO, it's allowed but you will have to pay more of the cost yourself.
• You pay deductibles yourself.

	Medigap	Medicare Advantage
How it relates to Original Medicare Parts A & B	Private supplemental coverage that pays all or most Part A & B deductibles and co-insurance.	Private health plan that provides Part A & B benefits directly in place of Original Medicare.
Premium	Average of about $150 to $200 a month. Can vary by age, health history, or both.	$0 to more than $100 a month depending on the plan. All plan enrollees pay the same regardless of age or health history.
Out-of-pocket costs	Low to none (not counting premium).	In-network medical deductibles and  copays of up to $3,400 to $6,700 a year, depending on the plan.
Choice of doctors and hospitals	Any that participate in Medicare.	HMOs: Plan providers only. PPOs: Any provider,  but out-of-network providers cost more.
When you can buy	First six months after you sign up for Part B and are at least 65 years old. After that, in most states you can be turned down or charged extra for pre-existing conditions.	When you first enroll in both Medicare A  and B and annually thereafter during Open Enrollment (Oct. 15-Dec. 7).
Part D (drug) coverage	Not ibncluded. You must buy a separate Part D plan for this.	Most plans include a Part D add-on. If not you can buy a separate plan.
Quality information available	No.	Yes. Medicare.gov has star ratings (5 stars are the best). Consumer Reports has Medicare Advantage quality rankings from NCQA.
Cards in your purse or wallet	Three. 1. Red, white, and blue Medicare card. 2. Medigap card. 3. Part D card.	Usually just one Medicare Advantage card (two if you have a standalone drug plan). Red, white, and blue Medicare card can stay in your desk drawer.
Paperwork	Little to none. Medigap almost always automatically cuts a check to providers after Medicare pays its share.	Some, because you pay deductibles and copays directly to providers.

Source: Comparing Medigap and Medicare Advantage - Consumer Reports News

Compare Medigap plans side-by-side

The chart below shows basic information about the different benefits Medigap policies cover.

Yes = the plan covers 100% of this benefit
No = the policy doesn't cover that benefit
% = the plan covers that percentage of this benefit
N/A = not applicable

* Plan F also offers a high-deductible plan. If you choose this option, this means you must pay for Medicare-covered costs up to the deductible amount of $2,140 in 2014 before your Medigap plan pays anything.

** After you meet your out-of-pocket yearly limit and your yearly Part B deductible, the Medigap plan pays 100% of covered services for the rest of the calendar year.

*** Plan N pays 100% of the Part B coinsurance, except for a copayment of up to $20 for some office visits and up to a $50 copayment for emergency room visits that don't result in inpatient admission.

See Medigap Plan Benefits | www.medicarerights.org

A broadly worded Social Security statute that prohibits physicians, pharmacies, and healthcare providers from offering valuable giveaways to entice Medicare and Medicaid patients.

Source: Secret to Getting a Pharmacy Discount With Medicare - Consumer Reports

An agent at our Senior Center vendor fair said they all get the same compensation whether you use an agent or go directly to the insurer directly and the compensation is the same for all companies.
At Senior Benefits Group they say this is not true.

• In most states, the first year you purchase a Medicare Advantage Plan, the agent is paid $429. If you renew a previous plan, the agent is paid $215.
• In DC, Connecticut, and Pennsylvania those rates are $483 the first year and $242 for renewals.
• In California and New Jersey the rates are $536 the first year and $268 renewals.
• Part D drug plans pay a $63 commission the first time and $32 for renewals.

NCQA > Directories > Health Plans > Health Insurance Plan Rankings > Medicaid and Medicare Health Plan Rankings 2013-14

Most states have an helplines.
See Find your State's State Health Insurance Assistance Program (SHIP) | SeniorsResourceGuide.com

Glossary:
Glossary at the Medical page here
Glossary | Medicare.gov
Medicare Interactive - Glossary

Links:
HiCAP (Health Insurance Counseling and Advocacy Program) 916 376-8915
Medicare & You | Medicare.gov
Secret to Getting a Pharmacy Discount With Medicare - Consumer Reports
Medicare Plan Finder for Health, Prescription Drug and Medigap plans | medicare.gov
Medicare Rights Center | medicarerights.org
Compare Medigap policies | Medicare.gov
Medicare.gov Plan Finder Tutorial from www.Q1Medicare.com
Health Insurance Ratings & Reviews - Consumer Reports
3 Mistakes You CanŐt Afford to Make | Senior Benefits Group