From Sand and Ash, by Amy Harmon, currently has a Whispersync deal price of $3.99.
I didn't know this before researching for this post (this is fiction; I don't read fiction, you may remember), but Harmon is a very prolific writer.
From the title is would probably be impossible to figure out the subgenre or even the genre, but it is basically historical fiction.
I've seen slightly less expensive WS deals than this one, but other than that, almost everything about the book almost perfectly matches what I like to post in a WS deal: it's very highly rated, at 4.7 stars at Amazon (and that's from 4,506 ratings!), it's got lots of pages (372). The only other downside, if you can call it that, is that the audiobook at Audible alone is only $9.95 (1 credit). But that still represents a big savings (60%), and with the WS deal you get the ebook.
Check into the book and WS deal for yourself at
this Amazon webpage.
This deal expires in 7 days.