The current line of Aura e-book readers from Kobo has everything you're looking for. They start at $129.99. There's the Aura (6 inch and cheapest version), Aura HD and Aura H2O (which is waterproof).
https://www.kobo.com/koboaura#overview
https://www.kobo.com/koboaurahd
https://www.kobo.com/koboaurah2o#overview