I complained about the official Voyage cover in my review of it — an origami case that flips over the top is an insane product for an e-reader. And I really like the official Paperwhite case!
Anyhow, I ended up buying this: http://www.amazon.com/gp/product/B00KD7ZRJ4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
It's weirdly solid and seemingly high-quality for a $10 knockoff, plus it's available on Prime. I'm super happy with it, especially for the price.