SpeechGeek Market offers a variety of debate briefs from a collection of different vendors. Free for download, these samples should provide insight into the quality and content provided by each of the brief publishers. If you're interested in ordering subscriptions for the 2014/15 competition season, you can visit the following pages.
(Note: New subscriptions will be added as vendors make them available in the near future. When you order a subscription, you will receive a pre-order notification. Once briefs become available, a link to the files will be sent to you via e-mail.)