I don't remember seeing any discount codes. Sometimes they'll offer a free book when you sign up. If there is an AHA rally near you, I hear those are sometimes discounted or at least you get some swag. Zymurgy mag is a good reason to join all by itself. Another thing to consider, if you listen to some of the podcasts like The Brewing Network or Basic Brewing Radio/Video, I think they both have links to join and they get a little bit of money to support their podcasts.