I have Unity free and I am looking for a free video making tool that works with Unity Free. Please help me. I can’t seem to find any help. P.S: It has to work with 2D videos, too.
Did you check the asset store? 
Yes, I did, but I need a free video making program.
If you are new to any development, what I would be suggesting you that every asset you need for game making, you have to model it your self in some external software or buy.
The word video making I think you are referring to animation, if that you can do it in Blender, Poser and Search for any other free Software.
Basically Unity is a great Engine which supports almost any file format and animation extension type which you externally import but basically an Engine is available to combine different Assets, Animations, Riggings and Script together to get a Final Product, You can develop some thing inside unity but in my opinion it wont be enough.