My personal list I got from sites online and have used, enjoy

FAN3 – 35% off . COM domains
PODFD412 – 35% off . COM renewals
FAN749 – 50% off . ORG domains
YUP749 – $7. 49 . NET domains
FED749 – $7. 49 . BIZ domains

Others I found in another post:
buck2 : $5 off if $30 or more
mopoff : $10 off if $40 or more
fan20: 20% off yearly hosting
fun1:min1: 10% off monthly hosting

Unique
radssl : $12. 99 SSL ( 56% Off )
auction12 : 50% Off auction accounts

Used some of these for a while now.  Print these out.