Yes it is good to learn Data Science at free of cost from You Tube . Because there are plenty of free videos available for learning Data Science. But most of them doesn’t provide same type of training. Go for the one which not just talks about theoretical concepts but also provides hands-on training. For that I would like you to watch this video offering by Intellipaat -
This video helps you to learn various concepts of Data Science from very basic level. By the end of this training, you will be having a better knowledge of Data Science.