I would use tynker.com for my students, I work with kids with special needs and so I think they would really enjoy learning how to code and this website makes it easier to learn how to.
We have a coding class at our school that can be a little advanced. I am also a special education teacher and think this would be a great resource to share with our computers teacher and students who may need some extra instruction.
We also have a coding class that is mandatory for 7th grade students at our school. It really gets students minds thinking and solving the steps of the codes. It can get pretty tricky.