Amazon offers the Crest 3D White Luxe Whitestrip 14-Treatment Kit for $30.08. Clip the $15 off coupon on the product page to drop that to $15.08. With free shipping, that's tied with our expired mention from four days ago and the lowest price we've seen. (It's also about $15 less than you could expect to pay in local stores.) These strips are designed to be used once a day for 30 minutes.