Rachel Sugar in Vox:
CVS is a drugstore much like other drugstores, with one important difference: The receipts are very long.
How long are the receipts? For at least a decade, concerned shoppers have dedicated themselves to this question, producing a robust body of phone-picture literature on the subject. You could not major in CVS receipt studies, probably, but you could minor.
Not all CVS receipts are created equal. If you, a non-loyal shopper, mosey into CVS and buy some Tylenol and a package of seasonal candy, you will get a receipt that is unspectacular (read: a normal length). To get one of the iconically long CVS receipts, you need to use your ExtraCare card, which means you need to be an ExtraCare member. (You can join as long as you are willing to turn over your name and phone number in exchange for better deals.)
More here.