As someone pointed out to me just now, the second volume of Scull/Hammond's new Companion and Guide is on sale as a Kindle eBook on amazon.co.uk for a nice £5 right now. Of course, volumes 1 and 3 are not on sale... You have to be in a region that allows kindle purchases from the uk site to be order to take advantage of this. Hopefully the other volumes will go on sale someday too.