If interested, I can sell you my sealed pack Amazon Fire 7 32 GB. It does not have google play store preinstalled but it is super easy to install (I can help). I already have another Fire 7 32 GB which I use daily for my TV show watching needs in company bus. I exactly know your use case as I do the same thing almost 4 hours daily in my commute.
I charge mine daily so when I leave house, battery is 100%, in mornings, I keep brightness at full so when I reach office, battery is around 70% and in the course of day, it will drain 3-4% when it lies in my bag and in evening I start around 66% and when I reach home, it is around 45-50% due to low brightness as it is mostly dark when I leave.