It might be a bit shocking to realize, but the 1977 film Star Wars was not necessarily a "big budget" film even by that period's standards.

It certainly wasn't the cheapest film, and the eventual cost of $11 million was over the original estimated budget (in today's dollars it's estimated to be about $45 million). An Annie Hall or a Saturday Night Fever, in contrast, cost some $3-4 million.

But compared to the other top-grossing movies in 1977, the budget for Star Wars was still mid-range. The Spy Who Loved Me - a Roger Moore James Bond film, cost some $14 million, Close Encounters of the Third Kind cost $20 million, and the World War II epic A Bridge Too Far with an ensemble cast including Laurence Oliver, Sean Connery, Robert Redford, James Caan, Michael Caine and many others cost $25 million.

There is a lot of history as to how Lucas pitched the idea, won studio financing from 20th Century Fox, and I will leave that to someone else who knows that specific part of the story better, but this might be some useful contextualization. As revolutionary as Star Wars was - and as much of a runaway financial success it turned out to be - it was not as an expensive movie to make as modern-day blockbusters are (including its sequels).