A system for automatically distributing discount coupons or certificates in a retail store, conditioned on a preselected combination of present and past shopping behavior of a customer whose order is being processed at a checkout stand. Generation of a printable discount coupon can be based on any desired combination of customer-supplied data, obtained from a customer identification data base, past shopping activity, derived from data gathered during previous customer visits to the store, and present shopping activity, as evidenced by items identified in the current customer order. Collection of data pertaining to past behavior of customers is facilitated by filtering all sales transaction data at the point of sale. If all of the preselected conditions for generation of a coupon are satisfied, the coupon is generated and printed at the checkout stand.