Grammaire CP-CM2 is not free (it costs 14.90), however it doesn't contain in-app purchases or subscriptions.
Not enough reviews to make a reliable assessment. The app needs more user feedback.
The price of Grammaire CP-CM2 is 14.90.
To get estimated revenue of Grammaire CP-CM2 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.