Have you tried with Amazon's service BookSurge? You might find it at http://www.booksurge.com/

I cite this because J. S. Milne (also on MO whose website is http://www.jmilne.org/math/index.html) published two books (one on Elliptic Curves, the other is a new edition of his very famous Arithmetic Duality Theorems) and prizes are extremely cheap for both. Nonetheless, I cannot saying anything on royalties, as I do not know, and heard some rumors that Milne himself was not so happy about something, but it may very well be false: why don't you contact him?