I see MSN is offering a $75 coupon for Adcenter. I just signed up and only had to pay $5 to get the $75. Go to Google Search and enter "ppc voucher" to see the ad. I found it by accident. Hey can't beat the price. It's not Google Adwords but I sure can use the $75.
If you don't have an account yet, it's a great way to test a new campaign, or for new comers to test the waters with $75 of basically free money.