Found this is the right time to Test Bing..
1. Create your Adcenter account.
2. Go to Bing Webmaster Tools. You will see in red "click here blah blah blah $50″. Follow the instructions after clicking on the link for $50 voucher.
3. Fill in your info here for another $25 bucks.
4. Purchase this Kindle book (Search Engine Advertising).
5. You'll need to email Kevin@KevinLee.Net with your Amazon order # requesting your Adcenter promo code.
6. Once you have that go here and fill in your info for a $200 voucher.
From the blog post here