My wife gave me one early. In the last three weeks, I have discovered the joy of FREE books (e.g., Beeke, Phillips, Sproul, etc.).
You really need to check the daily specials. Digital books often come online for free for a short period of time (often only for one day). If you download them, you get them. Otherwise, they revert to their regular prices. Secular books on Amazon are often $9.99. But Zondervan books are typically MUCH higher.
I picked up a GREAT case at Best Buy for $35 (M-Edge). It is light weight, faux leather, devoid of extraneous junk, and has a VERY solid protective cover with a soft micro lining. My wife uses the same thing on her Kobo.
For daily Kindle deals:
Amazon.com Bestsellers: The most popular items in Kindle eBooks