Primarily, a Kindle book cover, or more precisely six (6) nearly identical Kindle book covers.
I'm publishing a series of five Guides: The Money Counselor "Simple Guides to Debt, Credit, and Wealth Series." Each of the five Guides will be sold separately on Amazon as Kindle books, plus I'll offer a single book comprising all five Guides. So while it's six book covers, there should be continuity of design among the covers. I'm thinking of this is a single design with different titles/subtitles mainly, perhaps other minor differences at the designer's discretion.
To be clearer: I'm not expecting contest participants to submit six book covers. I'm expecting a single design, with the understanding that the contest winner will deliver that design in six versions differing only in the titles / subtitle, and perhaps other very minor differences at the designer's discretion.
I think I have a personal preference generally toward simplicity, structure, minimalism, clean lines, a more modern look. I think I'd like to see a wide variety of options from 99designs' designers, and I will provide feedback early and often to streamline the process. The book cover should be inviting, not intimidating, conjuring a reaction of 'this is going to be easy' rather than 'this looks too hard for me!' "Simple" is part of the series' title, and Amazon book browsers should have that sense from the cover. Success, particularly with money, prosperity, security, and competence are also words that come to mind.
I've attached the Money Counselor logo (which should be on the cover) and a document summarizing each Guide and providing titles and subtitles. Two versions of the logo are attached--feel free to incorporate either as fits best with your design.