This six-pack of Colgate Extra-Clean Full-Head Toothbrushes drops from $5.99 to $4.37 at Amazon. This is a small price drop, but it's the best deal we found based on any similar toothbrush pack. Check out the 93,000 Amazon reviews, which give these toothbrushes an average rating of 4.6 out of 5 stars. Shipping is free with Prime or when you spend $25. Otherwise, it adds $5.99.