I've been looking around on some websites, and while volumes 1-4 are running for around $10, volume 5 is running for around $35! My theory is that they didn't make as many, and beginning to think I won't find it at any BL. Someone prove me wrong!
I checked two big lots one had no anime but at the second one I picked up vol 3 of Zeta, 4 and 5 of King Gainer, 6 of Cowboy Bebop and The Best Sessions, thanks for the tip Chris