Indeed, VI App's subscription price on Apple In-App Purchase is based on your locality.
Quoted according to the prevailing currency exchange rates, the fee includes a service fee to Apple, a mark up and also GST (if applicable).
We therefore encourage you to subscribe to VI App via the web browser i.e. http://www.vi.app instead as it would be at a lower price.
*Please note that VI Ultimate is not available on Apple In-App Purchase