With today's computer technology, you can create way-cool business cards in as many colors as you like and in any amount that you desire. No more ordering 15,000 cards printed in two colors that are out of date after you give out the first 128. Your basic requirements are a computer, a printer, some business card stock, and some software. Since you probably already understand the first two, let's discuss the second two. A typical package will have 25 sheets, good for 250 cards.
Several sources are available.
Then you'll need a paper cutter to cut the cards apart after you've printed them. As for software, you have many choices. The one you may already have is to use your favorite word processor. Another software option is to buy a labeling program, like Labels Unlimited from Softkey. The advantage of this program is that you only have to maintain one business card image, and the program automatically prints ten of the same thing on the page.