Yes, Amity & Tiara 公式アプリ is completely free and it doesn't have any in-app purchases or subscriptions.
Not enough reviews to make a reliable assessment. The app needs more user feedback.
Amity & Tiara 公式アプリ is free.
To get estimated revenue of Amity & Tiara 公式アプリ app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.