Knife Sharpening Sharpener Stone | $15 | Amazon
Graphic: Erica Offutt

Update: Sold out

When used correctly, a whetstone (or water stone) can turn cheaper or dull knives into sushi-chef quality knives in just a few minutes. This $15 whetstone has two sides, one for the re-profiling, and a smoother side to hone. Typically priced around $24, today’s $15 price is a steal.