Just find it in the accessories section (under chargers) and use ACC20 as the promotional code.
You still have to pay tax though.
Got mine just now...should be here tomorrow.
(actually the code works for additional stuff too...but I was surprised it worked on the $29.99 price of the dock since it is supposed to be for items $30 or more. So if you want the dock plus the car mount you'll get $6 off each)