Hmm, not sure. I've never actually tried to pay for anything through the Fire. I had already purchased Domopad through another Android device before trying it in the Fire. I would have thought the process would be the same though. Did you check to make sure you were downloading the correct Google APKs for your version of FireOS? The underlying Android version does not match version numbers with the FireOS version so it takes a little digging and Googling to find the Android version. I'd check that first, also check to see if Google Play itself needs an update. I seem to remember it updating itself before.
Terry
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