Jokes aside, I was hoping somebody had an answer to Beagle's question. I've wondered about this myself.
The "beatz" market seems aimed at wannabe hip-hop artists, but every hip-hop recording I've ever heard uses some variation of the same beat; it's part of what defines the genre. None of them are particularly complex, at least not to the extent that anyone with a sense of rhythm couldn't easily come up with their own.