Samsung's is cool. I got up to like 200 points pretty easily, just from grocery store and coffee shops. You could bet 10 point to win more points (Twice I won 50 points) or you can gamble up to 150 points on things like vacations, Samsung gear and other items. I ended up gambling my points away, and not winning anything substantial.. but it's not like you should be able to win this stuff easily.
5,000 points can get you a $20 gift card it seems. That's 500 purchases IF you're at the base level, but maybe only 150 if you get to the higher levels. Not bad for something that's completely free (and more convenient).