I have had this book over a decade so the price could be different if you go to Amazon.com. But it is worth the price.
When I started my college degree (English literature) in 1998, my English professors recommended "The Elements of Style" as the book writers should have in their library. At eighty-five pages it has the best information on how to correct mistakes in writing. The information in this book can be used for academic papers, business letters, and even, fiction.
Recently, I started to do some writing on Helium, an online writing community. I was asked to help an ESL writer with her compositions. So I dusted of this book to see if I really remembered what was in the book. It was a great review for me. Unfortunately, I wasn't able to convince this writer to buy a copy. It would have done her a world of good.
Just to mention a little about one of the writers of this reference book. EB White is famous for his "Stuart Little" books about a white mouse who becomes a member of a family. This reference book was originally written by Strunk, but White when he was a college professor revised the book for modern readers. The original "Elements of Style" was written in1935.
In my opinion, this is the one book you need in your library if you want to be a writer.