All DH hosting plan comes with a free lifetime domain. The domain is free as long as you keep your hosting plan. How it works is that you will get a credit when you have your hosting plan. You use the credit to register one domain name for free for a year. When you renew your hosting plan next year, you will get another credit. Then you can use the credit to renew your domain name. That is how you get your lifetime domain.
Extra domain name means you will have the original free lifetime domain plus one more free lifetime domain.
I'm confused by your static and dedicated terminology as well. Maybe you can tell us why you need a IP address. As sXi mentioned, you will get a unique IP address by using the promo code. Usually the unique IP address is used for https.
$50 off and 3 free domains with code: [color=#CC0000]DH3[/color] [url=http://dreamhost.com/r.cgi?296804/signup|DH3]Sign Up NOW[/url] or More Codes Here