You have to pay what your health insurance plan schedule says.
They can charge whatever. Next time you go for an rx, see if the pharmacy will tell you what the cost is WITHOUT INSURANCE. In some cases it’s cheaper than your cost. But in every case the insurance company charges more.
Example
Prednisone. Cost without insurance $40
Cost with insurance $60, but you have a $10 copay
Insurance company gets the kickback.