10 Unfilmed Movie Scenes That Explain Crucial Details
3. Ferris' Source of Income - Ferris Bueller's Day Off
Given all the crazy things we see Ferris, Sloane and Cameron getting up to throughout this film, doesn't it require, you know, money? Specifically, money that a high school student likely isn't going to have access to? The script explains this away perfectly; Ferris has a chat with his father over the phone where he manages to trick him into telling him where some savings bonds are, which the young man promptly cashes in.
While one can see why John Hughes decided not to include this - it makes Ferris come across as a total douche from the outset - it does add some thorny fun and moral ambiguity to the whole thing; Ferris isn't just this care-free guy, and more to the point, it makes it clear that Ferris had to go to special effort to make this day happen. It is not a regular occurrence for him.