Power is OK.
Before spending more money on wifi what is the data allowance on your mobile phone? I have unlimited data on mine and I can tether to my phone and use that as a wifi hotspot.
If you have Amazon Prime or Netflix you can download movies or episodes of series to watch offline. My lad will download a handful to his tablet on a weekend when he’s at home and watch them during the week which lowers the amount of data he needs.