Yes, 壹时钟 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.
壹时钟 has several in-app purchases/subscriptions, the average in-app price is 1.50 ₩.
To get estimated revenue of 壹时钟 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.