Auper via Amazon offers the Auper 3-Stage Knife Sharpener for $14.89. Coupon code "3GA4TNE3" cuts the price to $5.99. With free shipping for Prime members, that's $9 off list and the lowest price we could find. It features a tungsten slot which repairs and straightens damaged blades, a diamond slot which provides general sharpening, and a ceramic slot which fine tunes for a clean polish. Deal ends September 30.