Keep in mind that availability and streaming options may vary depending on your region. Always ensure you're using legitimate sources to watch or purchase movies to support the creators and rights holders.
Platforms like Apple TV (iTunes), Vudu, and Amazon Prime Video frequently run sales. You can often snag the entire 4K Extended Trilogy for $30–$40, which is a steal for 12+ hours of content.
If you're not willing to commit to a subscription, you can purchase or rent individual movies on YouTube or Google Play Movies.
Occasionally, you might find clips or full episodes/movies uploaded to YouTube, but be cautious of the source. Watching copyrighted material for free without permission is illegal.
Do not underestimate the power of your local library.