Do you know how to find out what a given drug will cost with insurance, other than going to the pharmacy and ask them to ring it up (which takes several minutes

Do you know how to find out what a given drug will cost with insurance, other than going to the pharmacy and ask them to ring it up (which takes several minutes at my local Walgreens)? I've brought a GoodRX coupon to the pharmacy a couple of times, and every single time it's been cheaper with my insurance (which isn't anything special). The last time I did this, I was also puzzled to hear the pharmacist say that they "already had my GoodRX coupon in the system". I thought the coupon would be unique for each medication.