Amazon offers the Crest 3D White Luxe Whitestrips Professional Effects 20-Treament Pack for $35.99. Clip the $7 off coupon on the product page to drop it to $28.99. Plus, Amazon Prime members bag free shipping. (Non-members can spend $49 to qualify for free shipping; otherwise, it adds $5.48.) That's $1 under our mention from three weeks ago and the lowest total price we've seen. (It's a current low by $7.) These strips purport to remove up to 14 years of stains.