If stars also use the Neutrogena pearl facial cleanser that costs dozens of yuan, if professional make-up artists also choose Maybelline mascara, then what reasons do we have not to be more rational? You might buy body scrub that costs hundreds of yuan just because the sales lady said it could make your legs smooth and delicate immediately. A set of wrinkle-removal beauty cream which is said to be able to travel through time might be even more expensive than your phone bill for a month. "But most of the time, this money goes to the merchants, including market promotion fees and product packaging fees. Expensive doesn't mean high quality." This is the view in many MBA teaching cases. So, when choosing cosmetics, what is worth spending money on and where can you save money? The 80/20 principle of choosing cosmetics in this article may be helpful to you.