What is a Buk Email Address Broker?

How can I do bulk emailing without violating the C-S Act, while working for a legitimate brick and mortar carpet cleaning service? I have seen people selling packages of millions of email addresses for X$, but I am unsure where to mail these from as GetResponse, AWeber, and iContact autoresponders won’t accept them. I have already left a thread about transactional emails, so if anyone has any comments on that as well, I would appreciate it.