BetterBasics via Amazon offers the Sterline Adjustable Stainless Steel Mandoline Slicer for $19.99. Coupon code "SLICES26" knocks it to $14.79. With free shipping via Prime, that's $4 under last month's mention, $5 off list, and the lowest price we could find. It features an adjustable cutting size from 3mm to 9mm. Deal ends February 10.

Update: The price has dropped to $15.99 before coupon, $11.83 after.