Coursera is an online learning platform, you can learn the newest subjects form the best universities professors around the world for free, you can even get certificates on the exams you pass since your going to be involved on doing assignations and you will have to respects deadlines and you will actually learn amazing skills for free. A course I really suggest you to follow is " learn how to learn " the teacher are amazing and is a perfect start to this world.
This is considered one of the best learning company that makes tutorial for the most important software and subjects, tutorials are complete with exercises and you can do them when ever you want ! Let me know if you need a specific one I can provide it for cheap !
This website would cost money at some point but I think will give you a good coding knowledge.
It's a website at first confusing but you can learn a lot of new skills from it.
It's similar to duolingo but based on mathematics and science. Is an interactive website that will construct your technical skills form the basis.
This is a very good website but not free, not sure if it's worth it ! .
There's a lot of free documentaries..
It's full of papers and books and stuff to learn from google, a lot of schools use it as school digital library so you can find heaps of stuff.