Coupons for GREE in-app currency (iOS)
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I'm developing a game for iOS, and am looking at using Gree, and it's SDK for handle in-game currency.

This in-game currency will generally be bought buy users as in app-purchase. But, we might want to give out a fairly high number of 'vouchers' (that users could redeem to get e.g. the equivalent in in-game currency as they would get for a USD 5 purchase). 

Is doing this a violation of either Apple's or GREE's terms?