Well, Wildele, Diamond is out of several volumes, including 12, 14 and 16, so if you found all of them for $20, you're unusually lucky! (is your name Gladstone Gander?)

As for me, I feel lucky to have found a spanish language copy of vol 14 on ebay for considerably cheaper than the english copies are going for. (Thanks for the help David Tai!)

It would be great for the newbies if Dynamite were to reprint classic Spirit to spare them all this hunting.