You can check "JustWatch" or similar pages in case is somewhere else. If not...well you already know which is the only option apart from subscribing, piracy.
I mean for people that don't want to deal with piracy they can take note of the show/movie and when they have plenty of content pending to watch sub for a month or two and watch it.
Most of the time buying the content itself is not worth it, I mean I guess you can sell it back if is a bluray or similar but....
I mean my personal issue with it is that a lot of content is not that good to be like I will rewatch that and wanting a copy.
Like buying a tv show season just to find out is not your thing... sucks even if you still can sell it again.
For some stuff I would be tempted to buying a bluray or so but yeah not like the old days when it was the only way.