No, TriMeshImager is not free (it costs 1.99), and it also contains in-app purchases.
Not enough reviews to make a reliable assessment. The app needs more user feedback.
TriMeshImager costs 1.99 to download (and they also have additional in-app purchases).
To get estimated revenue of TriMeshImager app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.