Yes, 知室书院 is free to download, however it contains in-app purchases or subscription offerings.
Not enough reviews to make a reliable assessment. The app needs more user feedback.
知室书院 has several in-app purchases/subscriptions, the average in-app price is 283.82 zł.
To get estimated revenue of 知室书院 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.