I am going to sell a book series, how much is it valued at?

The book series I am selling is the first 9 books in the BONE comic books. The only downfall is that my name is written in 7 of them. I Each book is valued at $10 each, but I want to know how much I should put it up for seems I have written in 7 of them. It is only on the front page, so the pictures and book aren't technically affected. Please help