I was trying to sign up for an Google AdWords accounts today and wanted to get some free money (seriously, always look for a coupon code for when you buy/signup for things!)
I could only find expired offers that had come in the mail (they never are valid when I want it seems) so I was off to the searches. Google apparently does not like people sharing codes and ties them to an account.
So, where might I be able to find a free coupon code? A little google fu led me to this: http://www.google.com/search?q=site:http://www.google.com/ads/offers. A list of all their offers through partners/programs.
I realized I use some of those services (Google Analytics, thanks!). So I checked my Analytics email account and voila! Coupon code still valid (you can see when coupons expired if you click on the offers at the bottom).
Mission Accomplished: Free $100 in AdWords.