EDIT: sold - thanks!

Rarity: 150 Blackheart Hallow, lucky me. No idea how much to hold out for...

None in shops, 2 in galleries.. Which means you could ask for anything, really. However besides hoarders I cant see anybody shell out anything above 100mil for a book. :3 I want it myself badly but even with 50mil Id cringe. Still I'd say anything between 100- 50 mil probably?

Considering people werent paying 50mil for it during the reading drive I can only see a top end of around 30mil =/