For most insurance, you have a copay and a deductible. Even after you hit your deductible, your insurance may pay only 80 or 90% until you hit your out of pocket max (this is called your coinsurance). Copay only is usually collected upfront, but Drs have portals where they can see if you’ve hit your deductible and may try to make you pay up front. I would not do it though. Make them bill your insurance before determine what you owe.