Most health care services are covered by Medicare. In that event, the physicians or hospitals or other providers can list as a charge whatever amount they choose. However, they can collect only the amount allowed by Medicare. Therefore if you receive a bill for $500 and the Medicare allowed charge is $250, then only $250 can be collected. This will be collected from Medicare first and then twenty percent will be collected from your secondary insurance company. In the event you have a Medicare Advantage Plan, then that plan might pay your hospitals and physicians even less than Medicare, or perhaps more than Medicare. In any case, you are responsible usually just for your co-pay amounts. which are determined by your health plan. If you have only Medicare coverage, then your responsibility will be twenty percent of the cost allowed by Medicare.