Amazon offers the Comenzar 4.3-oz. Teeth Whitening Charcoal for $10.99 $10.39. Coupon code "KTTY2UKS" cuts that to $6.59 $6.23. Plus Prime members qualify for free shipping. That's $2 under the lowest price we could find for this quantity elsewhere. It includes ingredients like activated coconut charcoal powder and Bentonite clay. Deal ends June 30.