What are good websites to learn Autocad for free?

Youtube, but it's not free all times because you must pay money when internet participation is over

Autodesk itself is a good website, other websites include 

 quora, lynda, cadtutor, mycadsite, cadcorner etc.

youtube/dailymotion can also be visited.

Many Channel at youtube introduce autocad Courese , and here is one example .

https://www.youtube.com/channel/UCq1yrwFEVOzoSR6FOpIG1JA

I am agree with Experts...................

Youtube, Lynda, Tutorial Videos by torrents, Autodesketc.