Google is offering an online course on deep learning for free. The course is available through Udacity, a for-profit educational organization offering massive open online courses (MOOCs). It is estimated to take about three months to complete but you can choose your own pace. However, it is not for beginners, but assumes you have taken a first course in machine learning, and that you are at least familiar with supervised learning methods. The course also introduces TensorFlow, an open source software library for machine intelligence Google unveiled back in November 2015.

TensorFlow: Open Source Machine Learning.