This Cosrx Snail Mucin Facial Serum drops from $25 to $14.70 at Amazon This is within $0.20 of the special Prime Day price. It's been one of the top-selling beauty products at Amazon all year, with an average rating of 4.6 out of 5 stars from more than 56,000 reviewers! It uses natural snail secretions to smooth and hydrate damaged skin. It's hypoallergenic and safe for sensitive skin. Shipping is free with Prime or when you spend $35. Otherwise it adds $5.99.