This is a complety list of all current Godaddy.com promo codes. They should work as I am using them myself :-). Saved me already around 30 $ so far. However I suggest you, if you are living in the USA to use 1and1 as they are cheaper and have private domain registrations which is usefull if you are wanting to run a website that has DMCA-violent stuff on it.
OYH3 - $3 off / $6.95 any .COM (renewals too)
OYH1 - 10% off whatever
BTPS7 - 20% any order of $50 or more
BTPS4 - 10% off anything
OYH2 - $5 off a $30 purchase
chill1 - 10% off
chill2 - $5 off $30
chill3 - $6.95 .coms
hash1 - 10% off
hash2 - $5 off $30
hash3 - $6.95 .com registration
Good luck! Btw. posted in the right section?