The concept is simple: The church purchases gift certificates, or scrip, from popular retailers at a discount, which the retailers are happy to give because they're guaranteeing themselves customers and some goodwill advertising. Parishioners then buy the gift certificates from the church at face value. The difference in price is kept by the church. Parishioners spend the scrip at the retailer, where it's worth the full face value; they haven't spent an extra dime to help the church, nor have they had to change stores.