Yahoo SM, formerly Overture, publishes coupon and promotion codes all of the time. If you have registered a business, incorporated, or signed up for a free Yahoo Local listing (view the ventureN local listing as an example) you might have recieved a promotional code from Yahoo Search Marketing. If not, try this… USDM0149. This is worth $100 credit on a new account or $100 savings on assisted setup.
Visit using this link and you will see the promo code prefilled:
http://sponsoredsearch.yahoo.com/growbusiness
They folks over at Blogs and Bucks go into a bit more detail and show a simple method to look for a particular code that will give you $100 on a $5 open.