Yes, 아기 학습 - 힌디어를 is completely free and it doesn't have any in-app purchases or subscriptions.
Not enough reviews to make a reliable assessment. The app needs more user feedback.
아기 학습 - 힌디어를 is free.
To get estimated revenue of 아기 학습 - 힌디어를 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.