The thing about Kick-Ass (the comic book) is that Millar starts earning a percentage from the first copy sold. It would take quite a few copies before it would make up for not getting his page rate (which has to be astronomical), but once it passes that point he's gotta be raking it in.

He says that he made more on Kick-Ass (the comic book) than on any of his Marvel books. And since he's the one who sees his royalty statements (and probably pores over them lovingly for hours, and frames them and hangs them on his wall), I'm inclined to suspect he's right. The economics of a moderately successful creator-owned book have to be a lot more favorable than even a wildly successful work-for-hire.

As for movie royalties, that depends on the deal. The stereotype Hollywood net-points deal is such that the movie never makes a profit, no matter how successful it is. This, however, was made by Millar and Vaughn (and their financial backers), so the accounting will probably be gross-points and/or honest (i.e., George Lucas gave net points on Star Wars but was honest in the accounting, and the people who took them got mind-blowingly rich).

Medieval Guy, a.k.a. Rob Helmerichs
Former keeper of the Trade Paperback List