I've tried a lot of different kitchen knife sharpeners, and this cheap one is my favorite

This Kitchen IQ Edge Grip 2-Stage Knife Sharpener costs just $5.99 on Amazon. I've been using one for years and it's my favorite knife sharpener.  I like it because of the way you hold it with one hand along the edge of a kitchen counter and with the other hand you draw the knife through the slots. It's a safe way to sharpen a knife and I don't see how someone could make a mistake and hurt themselves. One slot is "coarse" and the other is "fine." I typically use the fine slot every week or so to restore the edge on a knife. I rarely use coarse because it removes quite a bit of steel from a knife, but sometimes that's just what's needed to sharpen a dull knife. Over 11 thousand people have reviewed this sharpener on Amazon, and has an average star rating of 4.3.