Does anyone know if in-app purchase can be gifted? For example, if I want to give a family member free coins in a game, is this possible?
The iOS SDK has a framework called Store Kit for handling in app purchases. The framework is only for collecting payment. As stated in the iOS Reference Library In App Purchase Programming Guide:
You must provide any additional functionality, including unlocking built-in features or downloading content from your own servers.
You would have to create the gifting functionality.
"Now using the StoreKit is there a way to submit a purchase with someone else's email? and not the current user?" I do not see a way to do this in the SDK.
When user 1 goes to buy an in app product for user 2, you will have to provide a mechanism for user 1 to select user 2. Then process the payment normally with StoreKit for user 1. Save the transaction on your server (what user 1 bought user 2). In your app when you check to unlock or download your in app products you will have to check your server for that authorization.