I designed my cards on Microsoft Publisher. It is one of my favorite programs! A little pricey, but worth it, IMHO. I can do just about anything with it, labels, cards, business cards, brochures, books, etc. Between Publisher, the internet, and a nice CD collection of clip art, the sky is the limit!!
I agree with others here who have mentioned printing them out yourself as you need them. I also have a Xyron 900 (My hubby spoils me with toys!) and I like to laminate my business cards and apply magnet sheet to the back so people can keep my card handy on the frig for reference!