When it comes to the value of Acos, it is generally considered that ACOS is less than 25% or even lower. For many new Amazon sellers, ACOS is a very vague question, but to put it bluntly, it is the proportion of advertising expenses to Amazon's sales revenue. According to different products and different purposes of sellers' advertisements, the ideal ACoS is also different. Assuming that the seller's advertising purpose is to promote product sales and improve the natural search ranking of products, then the seller's ideal ACoS is to ensure their breakeven. However, if the seller releases a new product, he may set a higher ACoS for himself. The seller's main purpose is to catch a long-term big fish. For mature product sales, when the seller formulates the ACoS of advertising, it is natural that the ACOS is low and good, so as to ensure that the seller can have good income every time he sells. However, if there is a higher profit rate, the seller can also appropriately increase the investment in advertising expenses to improve ACoS. Because although advertising products bring less profits, they bring more traffic and sales to stores.