Coupon code for Play Store: How do I use one?

[Guest kokotron]

Hello everybody,

I was offered a coupon code for an app in Play Store (after some dysfunctional-feature talk with the developers), but I have no idea how to use it. When I purchase an app (from the browser), I get to the point where I can only click "Complete the purchase", so I doubt there's another step beyond that, and no coupon code fields appear anywhere. Is coupon codes entry available only for certain countries?

Thanks in advance :)

Edited June 4, 2012 by kokotron