I recently found this great app called FeaturePoints, what this app lets you do is download free apps for points and get rewards for the points you receive. (You can delete the apps you downloaded after you get your points)
Once you reach a certain amount of points you can exchange them for rewards such as Xbox, Playstation, iTunes codes, or even have the points converted into money and transferred to you PayPal account.
To get this app you need to go to this link using an iOS or Android device: http://featu.re/F8ZHH7
Using this link will grant you an immediate 50 points to spend.