For those of you with cable ...
I have Spectrum as my cable provider. They have tiers of channel groups/offerings.
When games began airing exclusively on NFLN, I called to upgrade to the tier that included NFLN so I could watch the Bills game.
The rep told me that I could upgrade to the higher tier, watch the game, then call back and downgrade to the previous tier .... and that I'd only be charged for one day of the higher tier.
This is another option for those without smart TVs or Roku, firestick, etc., and it's easy/inexpensive.