[ghaff]

For older movies, you might consider getting a Netflix DVD subscription though they've let their back catalog deteriorate. (Your library is probably also a good source.) You can also just digitally rent a la carte on Amazon or Apple. By and large, the streaming services have never been great for finding a specific film.

[eggsmediumrare]

Seconding the library! Libraries are so great. And if they don't have something you want, odds are they will get it if you ask them!