Sam is an accomplished musician in the DFW area. He recently placed 3rd in the nation at the Philips Jazz Piano Competition, actively gigs around the area, and continuously composes music for Videogames, Short Films, and Advertisements and Commercials. He recently just finished composing theme/background music for a TV show in Nashville, TN.
Aaron Marks' book "The Complete Guide to Game Audio" has an excellent section on determining rates.
I just finished reading this book a couple weeks ago and the section on pay is phenomenal. It would do you, and every composer ever, to read the book, and of course the section hes referring to. I was scratching my head at some points wondering if people actually charged based off what he said, but it's legit and worth reading.
So the "qualities in a composer and their music" that let people charge a lot (per minute rates sometimes as high as 2,500), have as much to do about professionalism and reputation as the music itself.
Amazing point. Aiming to be professional is so important. I just cancelled working with this singer a couple hours ago because he's been late 5 rehearsals in a row. Professionalism is something I highly admire in all my colleagues and friends around me.