Based on feedback we've heard, and to encourage continued innovation, we are making AdWords API usage free for developers, starting March 1, 2013. Adwords API preferred pricing will be retired.
Going forward, there will be two levels of API access: Basic and standard. Basic access is provided by default and allows up to 10,000 operations per day. Standard access is available to qualified developers and has no daily limit on operations. With either basic or standard access, there will be no charges for AdWords API usage.
For more information check our announcement in the blog. #adwordsapi #free