It's $3.99, a novel is $7.99. What are you talking about?
It might blow your mind but not everyone here is American.
'In tempest's wake' - £3.99 - 99 pages
The eternal tide - £3.99 - 384 pages
Brinkmanship - £4.99 - 352 pages
Cold Equations book 1 - £4.99 - 368 pages
Did you get them from Amazon or The Book Depository? I tend to pay around a fiver from the latter, plus they have free postage.
I guess though, if you say brought the hard-copy versions from Waterstones, WHSmith (if they stocked them) or an Independent bookshop, you'll no doubt pay full price which then makes In Tempests Wake a bargain! But who actually buys books from bricks and mortar shops anymore?
Those prices are all ebook prices.