For example, I have a good half-dozen reward/discount club cards. Most of the stores just need the barcode, so what I like to do is photocopy the barcode side of the cards, put two together back-to-back, and “laminate” them with a strip of clear packing tape. Takes up a lot less room in the wallet that way.

Better yet is when they just let you use your phone number if you “forgot your card.” I tend to “forget” such cards constantly. Safeway actually lets you punch your phone number into the POS terminal while they’re ringing you up.