There are four things that determine how much your health insurance will cost you each month:

Premiums
A premium is the monthly fee that is paid to an insurance company or health plan to provide health coverage, including paying for health-related services such as doctor visits, hospitalizations, and medications.
If you have job-related insurance, your employer pays the monthly premium. Most likely, your company will require that you pay some portion of the monthly premium, which will be deducted from your paycheck. If you are self-employed, or buy your own health insurance, you pay the entire monthly premium.

Out-of-Pocket Expenses
Out-of-pocket expenses are what you pay for health-related services above and beyond your monthly premium. Depending on your health plan, these expenses may include an annual deductable, co-insurance, and copayments for doctor visits and prescription drugs.

Deductible
A deductible is the amount you must pay out-of-pocket each year for health-related expenses before your insurance policy begins to pay. Deductibles are common in PPOs for health care services received outside the PPO network. If you have Medicare, you will most likely have to pay a deductible for medical services and a separate deductible for medications under Medicare Part D.

Coinsurance
Some health insurance requires that you pay a percentage of the cost of covered health-related services after you have met your annual deductible. This is known as coinsurance and most often is about 20% of what your health plan approves.