system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that I can by a 2" thick novel for ~$6, but a 20 page children's book will cost me $15-20?
gpt
Books aren't sold by weight or volume. They're sold by what people will pay for them.

The children's book costs more because it costs more to produce (hard cover, color pages with images). They charge more for it because of that and because they know what people are willing to pay for them.