I think the best of these books (at least of the ones I've read) are in the $15 tier. Several of the books in the lower tiers are ones I'd recommend skipping and go to online resources, instead. It may not still be so, but when I last looked at the O'Reilly bash books, many years ago, the TLDP bash programming HOWTOs were more pragmatic and easy to follow (I think that's here: http://tldp.org/HOWTO/Bash-Prog-Intro-HO…
I pretty much learned bash from the man page (and OpenBSD's ksh(1), which has enough overlap with bash to be mostly applicable), enough to get by, at first, and getting more and more advanced by checking man recurrently as I encountered problems that demanded solutions beyond my skills.