We have been using Fresh Step cat litter for goodness knows how long. The other day I was looking at a bag and noticed something called "Paw Points", which can be redeemed for coupons or prizes. No telling how many bags we'd thrown away before I saw this...speaks well of my observation skills.
We've even thrown away bags since I discovered it. Anyway, just passing it along in case anyone is interested. All you have to do is register online and enter codes from the bags.