I dont sort out recipe cards in each different box, but if you cant find a small box, that would work well. I just altered my shoe box and put 4x6 index cards as recipe cards. I printed out 4x6, each recipe and covered 4x6 page protector as well. It works well for me since I can take one at a time and look at it while cooking.
I did put labeled index cards in front of each different types of recipes. Such as beef, chicken, desserts, etc. Colored index cards make labels easy to be recognized. I just put recipes after those index cards. Works well for me!