Yes, it will start out as a paid service. There are zero credible game creation packages today that output to it, and the lack of sound support will keep it in an experimental phase. It's still years before it's a viable technology, and the interesting angle isn't that it will replace Flash but that it will enable mobile games to exist outside an App Store. That is where 90% of the value is.
(I on older project with google ads encountered this and my site wasn't related to p0rn in any way)