Why lower the price of the initial purchase? Just keep it simple: basic app is $10 forever. The basic version of the app comes with some basic useful features.

Why lower the price of the initial purchase? Just keep it simple: basic app is $10 forever. The basic version of the app comes with some basic useful features. Premium features become available via in-app-purchase as the developer makes them. Users can choose to use the premium features or not. Bug-fix updates are just free as they should be IMO. Using a theoretical video editor as an example: $10 gets you basic clip cropping, placing clips next to each other, background music, importing, exporting and titles. So a basically useful app. Later the developer updates the app with a few bug-fixes and a premium "transitions" feature that's available via IAP. This update is of course free to download. So existing users get the bug-fixes for free. Anyone who want the premium feature just unlocks it and uses it indefinitely.