I have a Humana Medicare Advantage plan, and Humana has their own prescription drug service. It is called Centerwell Pharmacy, and they have all my prescriptions on record, update my refills automatically, and send a request to my doctor if a med needs a new prescription filled.
CenterWell also has the OTC (over the counter) allotment catalog online, so I order almost all of my vitamins from them now, too. the ones that they do not carry, I still get from Amazon.
However, if I didn’t have the Humana option, then I would definitely look into Amazon.