Have you checked out Shopkick yet? I've been earning points for the past 6+ months and I'm about to cash my points in for a Target gift card.
Sign up here.
Not familiar with Shopkick? Shopkick is a free mobile app for your iPhone or Android mobile smart phone. By allowing it to see your location using your GPS, it will automatically recognize when you enter a participating store, retailer, or restaurant, then reward you. You'll earn "Kickbucks" by simply entering the store and can earn by scanning barcodes within the store.