Total amount you will pay out of your own pocket toward your medical expenses.
A co-payment or co-insurance is just that — you and your insurance agree to co-pay for a healthcare expense. Insurance plans require you pay either a percentage or a fixed amount of the cost of a drug or health related expense.
The deductible is the amount of money you must pay out of your own pocket before your insurance will start paying/covering for other healthcare expenses. This can be a very small amount or thousands of dollars.
When insurances contract with venders who supply drugs or medical supplies, the venders agree to accept a maximum or discounted amount for various items.
For example, a pharmacy may charge $800 for a medication, but the insurance may only allow a charge of $650 based on their contract with the vender. The pharmacy accepts the $650 as payment-in-full. The insurance will pay up to $650, minus co-pays and deductibles.