If you want to make your own cards, they sell packs of blank cards at craft stores. I have gotten mine from Michaels. I usually buy two sizes: the standard card size and a thank you note size. They are white and come with envelopes that fit. The big ones come in packs of at least 50, - I'm not sure how many come in the smaller size. At around ten dollars, that's a pretty good deal - way cheaper then buying a five dollar card at the grocery store. If you don't want just plain white, they also have other options, colored and patterned, but I like the basic ones so I can customize them how I want.