Abstract: A method of validating a discount offer includes obtaining discount information from a coupon at a dispenser, the discount information including a unique discount identifier. The discount information is sent to a local controller, which attempts to communicate with a central system to validate the offer. If the central system is inaccessible, the local controller then compares the unique discount identifier with a local database of previously redeemed coupons. If the unique discount identifier is not found in the local database, the local controller approves the coupon and instructs the dispenser to reduce the amount charged to a customer by the discount amount. The local controller then adds the unique discount identifier to the local database. When the central server is again accessible, the redeemed discount identifiers are communicated from the local database to the central system.