Here is one of the best services i have found to earn apps giftcards and cash with your idevice or android. I like this app because of the world wide pay pal option.
Use this link on your device FeaturePoints or use my refferal code H7MQ0Yj and get a free 50 points
All you have to do is download apps and open them for 30 seconds and you are rewarded with points, now you can redeem your points for rewards such as paypal money itunes gift cards steam gift cards and a bunch of other things. thought this was cool to share ;P i can confirm that this works as ive already received 2 10$ itunes codes from them.
The concept is that developers get their apps featured on here, people download the shit out of them for points so they go up in the appstore making their apps popular, and people can get rewards for their points, its a big circle of benefits.