The one on this site is downloadable. You can't beat free. Even if you print it out it will be cheaper than any other source.
The book has a copyright holder who inherited it from The Connelly Brothers. If you look in new books it says his name under copyright. He has threatened to sue anyone who gives away or sells copies of it. That is why it no longer is on Scribs or forums on the net. I live 10 miles from him and resell them. I sell more copies in the USA then anyone else he tells me.