Yes, 数学1の王様‐定期テスト 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.
数学1の王様‐定期テスト is free.
To get estimated revenue of 数学1の王様‐定期テスト app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.