Hey! Can anyone make a ART cover for my story? I am writing a story with other authors and we want a cover! Can anyone make some for free? And if u need to communicate privately is it ok if we use FORUMS messages? 
I suggest to visit List Of Open Art Shops!
It is going to be easier for you and the others to look for open art shops and what you prefer.
There are free and paid art shops, edited and self-drawn ones.
And I think that most people do not have a problem when you pm them about it 