If you have an Android phone or tablet and want a quick way of checking your ebook sales on Amazon, give Afterword a try:
That’s the Play Store link. You can also search for “Afterword” in the Play Store app. Although I don’t have any Android devices so I can’t attest to how it works, it seems to be something I’d use if I did have an Android device.
Afterword currently has a 4.7/5.0 rating from 7 reviews, including a 5-star review from Hugh “WOOL” Howey.