I recently came upon a promotion of a paid iOS app that appears to generate App Store promo codes on the fly.
I thought you could only have 50 promo codes per app version. Where can I find more information about this dynamic promo code service?
I couldn't find a better Stack Exchange site to ask this question, and iTunes Connect does fall into the "software tools commonly used by programmers" category. Apologies in advance if the community thinks this question is off-topic.
I don't think anyone here is going to be able to help you, at least not without breaking non-disclosure agreements.
For the majority of apps, you have to make do with the 50 promo code limit within iTunes Connect. However, Apple will work with developers and publishers for larger promotions - for example, the free 'App of the Week' in Starbucks, or this IGN promotion you linked to.
There is no way for 'normal' or typical app store developers to get access to this. You need direct access to marketing/app store contacts at Apple, which is normally only available to developers of a certain size. I'm sorry it's not better news for you. If you are a developer of significant size then you should get in touch with Apple directly.