Gift Cards first came into prominence to replace gift certificates in the 1990s to help thwart counterfeiting. A gift card may resemble a credit card or display a specific theme on a plastic card the size of a credit card. The card is identified by a specific number or code, not usually with an individual name, and thus could be used by anybody. Some gift cards can be reloaded by payment and can be used thus multiple times.
Cards may have a barcode or magnetic strip, which is read by an electronic credit card machine. When you use the cards, they have no value until they are sold, at which time you enter the amount the patron wishes to put on the card. This amount is NOT stored on the card but is instead handled in the Theatre Manager's database, which is cross-linked to the card ID.