Creediting points to an iTunes account?

A potential customer of mine wants to build an app for the iPhone, which will effectively "reward" the user开发者_如何学C with points to buy songs at the iTunes Store. Does anyone know if this is possible? If so, could you point out where I might look for how to do so?

Thanks...

I dont think this is possible to do through any api. You could send gift cards... but you probably wont get into the store. Apple does not allow any kind of app that rewards customers with real-world items. I tried to submit a lottery app where buying the app would give you a ticket. It was rejected because Apple has no way to guarantee that you would actually give out any prizes. What if you dont? The only thing you can offer is unlocking features in your app, or digital gifts like stuffed-animal pics and such.