Apparently all list prices are not the same as each dealer sells them at different prices. I just got my Hawk brake pads in the other day. Guess I lucked out and contacted the right company. I bet you if you call each company listed on the certificate, each one will give you a different price. Some will charge tax if you are in the same state and also shipping and handling fees.
I figure that most larger companies will have a toll free number and their prices are usually better since they do higher volume and thus, might get a slightly cheaper wholesale price from the manufacturer which in turn, passes on to us, the customers.
Moral of the story is: If you are buying a pre-manufactured product, it is always best to check all the shops that sell them to see where you can save the most money. But then again, if money is not a factor, then you can roll the dice and choose from the list of vendors who will honor the certificate. My first contact was with The Tire Rack but since they didn't have the pads in stock, I called OG Racing.