I pass by a used book store on Thursday and check for Animorphs. It's a pain to buy used books online because of the separate S&H, so I took advantage of the physical opportunity. Didn't mind the $1.50 each.
The shop had everything from 2 to 39 (including 2 23's), Andalite Chronicles, Megamorphs #1, and Alternamorphs #1. All of them are in great shape. Score!
I needed 3,7,10,18,19,20,24,29,30 and 32. Megamorphs #1 gave me all four of those. I've heard Alternamoprhs stink, but I'm a completist collector nevertheless.
I have 8,12,31,38 in less than stellar condition. Maybe I'll go back to upgrade those.
If somebody's interested in any of the rest, let me know and I'll try to pick those up as well.
Still looking for 1,40-42,44-54,Alternamorphs 2, and a paperback of Visser. I have 43 in crap shape.