To provide mobile device coupons and discounts, a mobile device couponing system is provided to generate and send coupons to mobile devices based on a probability that the mobile device is within a defined region. The value of the coupons can be inversely proportional to the probability that the mobile device is within the defined region. The probabilities can be precomputed by calculating the probability that each cell in grid in or around the defined region is in the defined region using a set of standardized location resolutions. When location information is received from the mobile device, the probability that the mobile device is within the defined region can be retrieved based on the closest cell that matches the location indicated in the location information and the standardized location resolution closest to the location resolution indicated by the mobile device.