Turn a coupon into a business card (or vice versa).
Coupons are seen everywhere; you clip them from the newspaper to save on groceries, you get them in the mail to save on brand name items, you even get packages in the form of booklets delivered to your door. Almost everyone believes in doing coupons. I always look to see if a restaurant I love is having a promotion and if my favorite ice cream is on sale at the grocery store, and I imagine that most people are the same. I am driven to using the coupons because I regularly purchase the item whether on sale or not. Restaurants use coupons to bring new people into the establishment. Some people even have a filing system for coupons and make a hobby of collecting coupons and making money in the process. I am not suggesting you go that far, but you can use a business card for a coupon.
If you want a customer to purchase your product for the first time and you happen to know that they are already interested, offer them a coupon on their first purchase. Retailers that want new customers for their credit cards do the same thing. Once they have the card in their hands, it is more likely that they will spend at the store. The same is true for any business that wants new customers and also wants to form new business relationships. Hand them a discount coupon for either your products or services, or you can make arrangements with a local restaurant to purchase coupons for a free meal.
Coupons are an excellent additional way to keep a business relationship alive. When I worked in a marketing department, my favorite thing was when our suppliers gave us tickets or coupons for special events.