We carefully examined the notion of bringing the complex iOS client development in-house, however due to our limited resources and expertise in this area, most of the iOS development had to be outsourced.
As a relatively small company, we could not bear the development costs without impacting our current resources and objectives.
For this reason we had to place a small fee on the iOS client in order to help offset these costs. We have carefully studied the effects of our decision, and can assure you that the vast majority of our users have had no problem paying the one-time fee of $4.99 USD.
Please keep in mind that after paying the one-time fee, all subsequent upgrades of the TeamSpeak 3.x iOS client will be available to you through the Apple Store free of charge.