Weird...
I wonder why that freakin' book is thought to be worth over $500...???
http://www.amazon.com/Nations-Shall-Know-That-Jehovah/dp/B000IDQCZ6
That would be because the seller is delusional. It is only worth what someone would actually pay for it, not a delusional number slapped in place. It would likely sell for $1-$5, maybe double that. It would be worth that much if there was something you could show to a JW and see the look on their face.