This app was mentioned in 1 comment, with an average of 2.00 upvotes
I don't know of a free version. Devi Mandir publishes a great version though. You can get as an app on both Android and Apple devices. The app also has a Sanskrit only version included. Here's the Android link- https://play.google.com/store/apps/details?id=org.shreemaa.android.Rudrashtadyayi