Hey,
You can always visit the Wattpad Clubs under the "Community" tab and check out "Multimedia Designs". People create covers for each other there. Just be sure to read each individual creator's criteria.
Or if your any good with Photoshop you can find a free image offline and whip together one yourself. (That's kind of tough even for me though, but I try my luck with it because I never explain my vision well enough for others. :P) Anyway, hope that helps. I'm no expert here either, but I offer a bit of advice when I can. ^^ Just ask me, if you'd like. @Hot_Broody_Wolf