Bought two 1TB USB powered drives for $50 each shipped from Amazon on sale a couple of weeks ago. I bought them for offline backups but it shows the prices are falling on the smaller drives now that 4TB are becoming common.
We don't watch TV in the camper but if we did I with proper compression (yes you loose some quality but you're camping rough it :-) you should be able to get them down to less than 1 GB each so you could put a bunch of them on a thumb drive. I bought a cheapy 32GB thumb drive off eBay for $8 shipped a few weeks ago.