If a developer wants to give some paid content away, usually the best way for them to do this is with a Google Play promo code. This has always been dependent on where you live, as they're supported in some regions but not others. Now, Google has added 8 further countries to the list of those that support the codes. They are as follows: Belgium, Finland, Greece, Ireland, Netherlands, New Zealand, Portugal, and South Africa.

Play Store promo codes can be used to purchase content or add funds to your credit balance. They are a handy tool for developers who want to gift IAPs or whole apps to certain users without having to alter their pricing structure. With the new ones added, here's the full list of countries able to make use of promo codes:

Source: Google Play Help