Huge number of people who need business cards mean huge profit from there. Yes you got just a few dollar or maybe few cent from it. But if you get more customers you will get more dollars inside your pocket or bank account. From my source, a box of full color business cards contain about 100pcs of cards price is about $10. With $7 for production cost, you have $3 as your profit. Now, think about number of people who need business cards. You can equal it by yourself. The number of people who need business card is greater than people who need full color brochure printing or full color postcard printing.
Business cards printing is the great business for you who runs printing business.