Avengers: Infinity War may be the biggest Marvel movie to date, even bigger than Black Panther, which broke half a dozen records in its first week of release. The 19th film in the Marvel Cinematic Universe, this "beginning of the end of Phase III" film is the culmination of the story that began back in 2008 with Iron Man. For those who need to get caught up before the film arrives, the most important film is the last time all our heroes teamed up. Here's where to stream Avengers: Age Of Ultron, as well as where to stream most of the other films as well.
Fans need to understand that there isn't an easy answer here. It's not like one can just log into Netflix or Hulu and watch all 18 films in a row in one place without paying a fee per film. That's actually deliberate on Marvel's part.
As you may have heard, Disney is currently working to create their own streaming service, like Netflix, but only Disney content. That includes not only the classic Disney archive but all the new Star Wars films (and all the old ones too, once the FOX merger goes through) and everything Marvel related, including the ABC TV series.
In preparation for that, they've cut off the deal with Netflix they had signed back in 2016, and they're not extending any other deals they currently have going once they end (like TBS or HBO/Cinemax). That means any film which was part of a deal that ended already is only available streaming for rent until the Disney service launches. That includes everything from Phase I except The Incredible Hulk.
So if you're looking to stream the original Iron Man or The Avengers from 2012, they only way to do so is via streaming rental. For Avengers: Age of Ultron, there a luckily a few more options. Let's run them all down.
Amazon Prime Rental Streaming
For fans looking to stream every Marvel movie available all the way back from 2008 in one place, those with a Prime account are in luck. Amazon has the rights to rent everything up to Thor: Ragnarok. Rentals cost $3.99 a pop, but the library is complete, and if fans decide they need to own the film, purchasing power is right there for $16.99.
Google Play Rental Streaming
For those who don't have a Prime account and do have an Android device, Google Play is the best option. Like Amazon Prime, they have the right to rent and sell every Marvel film. (Yes, even The Incredible Hulk.) Rentals cost $2.99 a pop, and buying the film costs $12.99, so it's even a little cheaper.
YouTube Movie Rental
YouTube's move into movie rentals occurred a few years back. Personally, I'm not the biggest fan of their interface, but your mileage may vary. They do rent all the Marvel films though, through YouTube Movies "from $2.99 and up," so if you're really into YouTube, this is probably the method for you to do a Marvel catch up.
As I mentioned earlier Disney is making the move to create a digital platform of their own in the next few years, where all their films will be available for streaming, Netflix style. One of the reasons for this is that the streaming and airing rights for series like the MCU are currently scattered hither and yon. (For instance, Cinemax has the rights to Hulk but nothing else.)
In a deal made back in 2014, Turner Networks got the rights to five of the films, starting with 2015's Avengers: Age of Ultron. But then two years later in 2016, Disney made a deal with Netflix, so they only wound up with Ultron and Ant-Man.
Still, if you have basic cable, you have TBS, and can log into their streaming site and watch with your cable log-in.
It's Not On Netflix, But Civil War Is
As just mentioned, Netflix made a deal with Disney in 2016 to start exclusively streaming the Marvel films after they left theaters and were released on Blu-ray, starting with Captain America: Civil War.
Sadly, that doesn't include Ultron. But when it comes to getting caught up ahead of Infinity War, Civil War is just as important as Ultron (and covers most of the new characters from Phase II and III), as it's basically Avengers 2 ½: The Smell of Civil Liberties. So once you're done streaming Ultron, head over to Netflix and watch Captain America: Civil War, and you'll be all set for Infinity War's premiere.
Unfortunately, Disney cut off the deal a year later, so they only have Civil War, Doctor Strange, and Guardians of the Galaxy Vol. 2, available to watch on top of their own Marvel Netflix TV series.