Any IOS games that you can earn money/gift cards/rewards from playing?

All the games that advertise this usually are complete scams. Another game I play is called MyVEGAS slots where you actually do earn loyalty points by playing, and can redeem vacations and free credits at casinos in Las Vegas. However I am looking for something that is more practical. It can even be just walmart gift cards or anything really, just not Las Vegas vacations or cruises for free.