Career Day, by Barry Lyga, is free to pre-order in the Kindle store. It does, unfortunately, come with a bloated, 10-chapter sampler of his upcoming novel, but you can still the advertising copy and just read the short story. If it weren't for the included short story, I would not even include it here, as it only encourages the publishers to continue using these to jack up their sales rankings (and to falsify their "books sold" numbers). Currently there are 33 of these free in the Kindle store (including two by indie authors!) and that only includes the ones that actually admit to being "previews" in the title; "excerpts" and "samplers" add nearly 40 more to this number.
Book Description
A 3,000 word short-story prequel CAREER DAY!
When your dad is a serial killer, things like Career Day don't go over so well. While classmates might be looking forward to joining the family business, Jazz knows he needs to find a new path in this original short story by Barry Lyga.