Which is the best course for data science?

Hi,

I am looking for the tutorials, articles, examples and courses for learning highly popular machine learning technologies. I searched many examples on the internet but found that it is difficult to learn Machine Learning and Artificial Intelligence. So, looking for the best training courses which can teach me data science very well. I want to learn the data science in 3 to 6 months. So, which is good course? Which is the best course for data science? Is there any free or online course to learn data science for free? I am looking for the help from the industry experts and looking for the best information on machine learning.

Thanks