Yes, 심리학: 세부적인 마음 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.
심리학: 세부적인 마음 is free.
To get estimated revenue of 심리학: 세부적인 마음 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.