What about AquaSport in Marda Loop?
http://www.aquasportscuba.com/index.html
I don't have any dive tickets but when I was looking for snorkeling gear (Ok this is about 10 years ago so maybe things have changed since then), I shopped around and found that gear (and the courses) were WAY less expensive with these guys than at Adventures or at the Dive Shop. They had their own pool too.