Yes, HIIT&カーディオワークアウト 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.
HIIT&カーディオワークアウト has several in-app purchases/subscriptions, the average in-app price is ¥3.50.
To get estimated revenue of HIIT&カーディオワークアウト app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.