These are the best coupons (update) I have found on the internet (tested!):
“SAVE57″ – save up to $57 depending on hosting plan and payment (montly or yearly)
“UPTO97OFF” – save up to $97 depending on payment type and hosting plan.
“FREEDOMAIN41″ – free domain name and $41 off – any hosting plan
“FREEIP21″ – Free dedicated IP address and $21 off
“COUPONMAX” – maximum discount on any hosting plan.
Use any of the coupons when you signup with Dreamhost. Coupons never expire.