Where to learn free unity scripting

There are always somethings out there that are free. Here is what I just know. I haven't tried it yet. But I'm sure you will find it very useful.
Walker Boys Studio

I see there are lots of videos tutorial in Walker Boys Studio. So it's a good idea to check it out.

There are also few others such as : Unity3DStudent and Tornado Twins Tutorial.

I hope this will guide you to understand clearly about scripting in Unity.

I know this is a bit old but stumbled across it.

http://www.codecademy.com/#!/exercises/0