As BlackBerry Dev Alpha C devices were rolling out to developers not long ago, it was spotted in BlackBerry 10.1 that BlackBerry was exploring the idea of 'coupon codes' or promo codes as they're now described. As an example of their possible use, developers could give out special codes as part of a promotion so you can get their paid app for free or with an discount just by entering that code.
A new BlackBerry Knowledge Base article has been published that offers up some further details on the matter. More specifically the error codes that are possible in certain scenarios, which in turn offer up a look at how promo codes could be used once made available to everyone:
Looking at the error, it's pretty easy to place some situations behind them. Codes can be limited to a certain number, time, locale, device and even wireless carrier and more.
Additionally, the document also notes 'Once a promo code has been entered tapping the Promo Rules button will display specific rules about the promotion such as promo time duration, number of redemptions per code, total number of items available per code.'