Google continues to push the envelope for Internet business models.  From Customer World.

Google says it will make a large number of online coupons available at no charge to consumers via its Google Maps service, while AdWords marketers have the opportunity to pay for a coupon-link alongside their ads.

The methodology is not yet developed for how this will work, with several alternatives.

Cost per download model – Pay per coupon downloaded( base level pricing)

• Cost per redemption model – Pay a little premium if the coupon gets redeemed
• Cost per repeat use model – Being Google, they can track my usage and hence if the same customer is redeeming the coupons for the same brand, they could charge a higher premium to the brand than the first download