A promotion code is a special offer from Microsoft Advertising adCenter. You can acquire a promotion code through Microsoft promotional events, from online marketing drives, or through other special offers. A promotion code is redeemable for a defined amount of adCenter service at no charge. For example, if you have a promotion code worth $50, and then you accumulate $100 in charges for your campaign, you will only be billed for $50. Each promotion code has a specific dollar amount and an expiration date. Sign-up promotion codes are valid for up to five days after you’ve created your adCenter account. All other promotion codes are valid until their expiration date. give this a try and see how it works for you. dean
I couldn't find a free voucher, but I did find something almost as good ... I bought this book 'Search Engine Advertising: Buying Your Way to the Top to Increase Sales' from Amazon (cost about $15 for Kindle edition) and got $200 Adcenter credit. The book is actually pretty good too.