Yes, 梦溪笔坛 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.
梦溪笔坛 has several in-app purchases/subscriptions, the average in-app price is 38.23 S/.
To get estimated revenue of 梦溪笔坛 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.