I didn't know that they just released another - this review has a nice feature where you can see the changes between the screens, pretty cool.
http://www.theverge.com/2015/6/23/8830663/amazon-kindle-paperwhite-review-2015
In terms of big savings.. its kinda new, and its kinda cheap (relatively) so there isn't a lot of 'juice to squeeze' in terms of finding discounts...
One little thing I did recently was buy Amazon giftcards at an office supply store with an Ink.... you get 5x Ultimate Rewards, which I'd say is about 7% rebate. You can go through portals for Amazon like TopCashBack, but they often exclude items like this for cashback (I go through even if they say they are excluded because I'm optimistic.)