I have carried my Just One Club Card around since 2006. This free site allows you to consolidate up to eight different bar-coded store loyalty cards into a single card that you can print out. Just enter the bar-code numbers in the form and select the store from a pull down menu, and click the “Create your Card” button. Instead of carrying around a bunch of cards in my wallet or key chain, I now have all of them on a thin piece of paper that I’ve laminated with packing tape.
Every time I whip it out to make a purchase it never fails to get a comment from the cashier about what a good idea it is.
[The FAQ section of the website has a template for a folder with a cut-out window so you can slide the appropriate bar code into view for the scanner at the store you are visiting. Also, the "Create your Card" button is hard to find -- it's between two banner ads at the bottom of the page. -- Mark Frauenfelder]