Costco Pharmacy does not require membership
For those who don't know already: the pharmacies inside Costco do not require a Costco membership! Canadian law requires that pharmacists dispense to anyone, so they can't limit their customers to Costco members. From my experience, prescription drugs are usually quite cheap there and the dispensing fee is very low as well.
If the greeter at the door asks for a membership card, simply say that you want to go to the pharmacy and you are in!