Here is a review I wrote at epinions.com with a link to a seller of a vertical business card holder. Remember that most cards are horizontal. If you have a vertical business card you might want to check this out.
This is a very handy device for displaying business cards. What makes this unique, in case you missed the point, is that this business card holder is designed to display cards VERTICALLY! Most business card holders are manufactured to display the card HORIZONTALLY. So for those of you who have VERTICAL cards (like my wife’s business The Lake Shore Music Studio) this card holder will allow you to display your card in the proper direction. This looks nicer and displays the information better. Business card holders can be used at your own place of business for sure. But think about creating alliances with other complimentary businesses, then see if they will allow you to display some cards in their store or office. An alliance like that is great for local trades people, real estate agents, chiropractors, auto repair and other service providers.
These clear acrylic holders are pretty sturdy. Typically acrylic like this is sonic welded rather than glued and stay together pretty well. Since the price is just a tad over a buck any small business should be able to afford to use them and display them around town. They are sold as 10 pieces minimum so start thinking of some places you can use them.