What is the flat fee you pay every time you receive a covered service?

The flat fee you pay every time you receive a covered service is known as a co-pay. A co-pay is a predetermined amount set by your insurance plan that you must pay at the time of receiving services, such as a doctor's visit or a prescription. This payment structure is designed to share the cost of healthcare services between the insurance provider and the insured, encouraging the insured individual to seek medical care without financial barriers for each visit.

In contrast, a deductible is the amount you need to pay out of pocket for services before your insurance begins to cover costs. A premium is the regular payment made to maintain your insurance coverage, regardless of whether you use healthcare services. Out-of-pocket expenses refer to the total costs that you incur for healthcare services, including deductibles, co-pays, and coinsurance, but do not specifically refer to the flat fee paid at the time of service. Therefore, the definition of a co-pay best fits the description in the question.