I use them all the time and my mom showed me a fun way to organize my recipes. She has a photo album for 4x6 picture slots and has organized her cards in there. It is fabulous way to keep everything in one spot.
The set comes in a package of 25. You can mix and match the colors how ever you want or request custom colors. Cards are printed on 110 lb Card Stock.
These make a great gift and are fun to have at events like bridal showers. I can also print double sided if more space is needed.