RetailMeNot

 Available on Computer, Google Play,  and Apple Store:  

What it does -You Punch in the Medicine you’re Searching for, it Looks up that Medication in Every Single Available Pharmacy in the Area, with a Radius of up to 50 Miles, Giving you a List of Each as well as the Prices of Each Med.

Once you Select the Store it Gives you a Coupon (That works even if you have insurance) to get your Meds at the Specified Amount. This Service is Completely Free.