None
I've never seen one other than the regular renewal ones in the "In Light of the End of the Godaddy Loophole" post. These codes won't reduce TDNAM's fee, or the winning bid price, but they will drop the price of the domain registration feee from $9.95 to $6 or $7.
It would be nice, however, if we could get a 10 to 30 percent break on our winning bids; but that just ain't going to happen. So we'll just have to settle for the $2 to $3 savings on reg fee.