I've never approved of Holly Black and Tony Diterlizzi's Spiderwick Chronicles. At $10.99 per (short and v. unsatisfying) book, the series has always seemed like a total money sink. But when I saw a collected version of the first five Spiderwick books I thought I might check it out... until I saw the price tag. It's still listed at thirty dollars! For a 569-page-long kids' book!
For the purposes of comparison, you could buy:
A) A boxed set of the first three books in the Percy Jackson and the Olympians series by Rick Riordan for $19.99,...all three of which would be a much, much, much better value.
B) The complete boxed set of the Underland Chronicles by Suzanne Collins for $32.95, or
C) A boxed set of the first five Artemis Fowl books by Eoin Colfer for $35.00...
I'm just sayin'.