Although you can download the app from Amazon, you can’t install it on your Android device without making changes to the normal security settings. Go to Settings>Security and then check the “Unknown Sources” box to allow the installation of apps from both trusted and unknown sources.
Then open Downloads and tap on “Amazon_App.apk” to install it.
It’s up to you to decide if “actually free” is worth it.
Amazon launched Amazon Unlocked, a similar program, back in March. With the launch of Underground, Amazon quietly killed off its Free App of the Day. However, Amazon Underground is meant to be a long-term program, so Amazon will “continue to invent and add more benefits.”
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