Sometimes it's fun to be done with all your book club books way in advance. It means you can finally read the books you bought on your Kindle about a year ago because they were cheap and they looked sorta interesting. I'd heard about this one, and heard it was a "kid's" book in the sci-fi/fantasy realm. For $2.99, why not?
I won't presume to understand why publishers decrease costs on certain volumes. If it's because they think they won't sell at regular prices, then, why this one? It's not a stand-alone book, has a decent following, and isn't remotely boring. Colfer has written an engaging theme (fairies exist and humans want their gold) set in a land he understands (current-day Ireland) with characters that act human even if they're not (yes, even fairies have to deal with tourists and gridlock).
He is definitely writing for kids, that's obvious. Heck, his main human character is 12 years old. There's a thematic undercurrent highlighting all the things we as humans are doing to hurt the earth (popular with teachers and parents, I would guess). But man, is this violent! I understand he is doing that to make it feel, um, more real. It does make it a little harder to swallow as a book for 12 year olds, though.