We love a waterproofed Kindle, and we put one through hell, but that's an aftermarket mod, not a feature that comes standard. If you want waterproofed reading on the cheap(er), the new Kobo Aura H2O is for you.
Offering IP67 certification (waterproof for up to 30 minutes in 3 of water if the port cover is closed) and a 265 DPI e-ink display that's tied with the more awkward Kobo Aura HD for highest in the world, the Kobo Aura H2O is great for a beach- or tub-reader who can remember to keep the flap closed. And starting at $180, it's a damn sight cheaper than a $240 waterproof Kindle. You can pick one up on Kobo's website starting October 1st.