How do you ask a company for a handout? (see details)

I am starting a student organization at the University of Illinois called Dance Destruction. Our goal is to have awesome alcohol free parties at random places around campus. I am going to put together an awesome sound system, light show, and everything.

Out funding is very limited, so I was going to email several speaker companies (like Bose) and ask if they could either give us free equipment or maybe even just a reduced price on some stuff. In return they would get advertising (via logos, exposure, and testimonials from me).

My question is this… What should such an email include? How should I word the important stuff? How should I word the small stuff?

I just want to maximize our chances at getting a really good deal and getting this club off to a great start.