As of 2015, Spider-Man is the most popular superhero based on revenue generated, according to ComicBookMovie.com. He grossed over a billion dollars in 2014 for Marvel Comics, the company that owns the character.
The next-most-popular superhero is D.C. Comics' Batman. While Batman is subjectively as recognizable as Spider-Man, the character is not even half as profitable as the Spider-Man franchise based on 2014 revenue figures.
Marvel's Avengers, a group of superheroes, have also been quite popular in the last few years and include such heroes as Iron man, Thor and Captain America. The value of Avengers-related products sold in 2014 alone was approximately $325 million.