Despite the fact that the studio calls the United States home, several of Marvel’s movies have taken filming overseas, whether it was South Africa and South Korea for Avengers: Age of Ultron or Captain America: Civil War recently wrapping up a shoot in Berlin, Germany. Although Phase Three has only just kicked off, the studio is now looking ahead on how to handle production for more of their upcoming cinematic adventures. In the case of Thor: Ragnarok and Captain Marvel, both are being considered for filming in a place the Marvel films haven’t visited yet, Australia, and it's pretty much just because of the reason you're thinking: money.
According to an anonymous source that spoke with Yahoo!, Disney had such a "great experience" filming 2016’s Pirates of the Caribbean: Dead Men Tell No Tales in Australia that the studio is considering filming either Thor: Ragnarok or Captain Marvel (or possibly both) in the Land Down Under. This source (who was a technical specialist on the fifth Pirates movie) also said that this move would also save money on location scouting since the studio is already familiar with the area. They said:
It was a great experience for the studio who were able to familiarise themselves with the set-up at Village Roadshow (studios) and the crews here. They were also able to work across a lot of different locations which has saved them scouting for the Marvel movie.
The article notes that there are multiple upcoming blockbusters heading to Australia, including Kong: Skull Island and an untitled Sony tentpole project, as its a prime filming destination because of the Australian dollar "hitting a six-year low" - thus allowing the studios to get more with the American dollar compared to previous years (specifically with US$1 equaling about A$1.40). Should Marvel choose to film Thor: Ragnarok in Australia, this would be great news for native Chris Hemsworth, who currently resides in Byron Bay with his family only an hour drive from where many films are shot. The God of Thunder’s third solo film was originally set to begin filming around June 2016, but if Australia is chosen as the shoot location, the production would evidently kick off in March of the same year. As for Captain Marvel, that likely wouldn’t begin filming on the continent until early 2017 since it’s not being released until late 2018.
Assuming that Marvel decides to bring only one of their movies to Australia, Thor: Ragnarok seems like it would be the better choice. The 2017 blockbuster is set to follow Thor, Loki and the rest of Asgard as they deal with the apocalyptic event that will result in their destruction. Presumably most (if not all) of the film will take place away from Earth, thus allowing Australia’s more colorful locales to be used as other worlds within the Nine Realms that Thor and the other Asgardians may travel to.
Thor: Ragnarok will hit theaters on November 3, 2017, with Captain Marvel following on November 2, 2018.