Hi Gabor. The current djay app on iOS is a free download, with a subscription for the PRO features and content. The ongoing subscription model allows us to continue developing the app and continue to add new content. As such, there isn't any way to offer a one-off payment option with the same parity.
If you previously purchased any of our legacy apps, you can claim a special loyalty discount of six months free PRO subscription. The annual payment option also saves you 30% compared to the monthly cost.