If you are planning to build a business or even if you are just a consumer, I believe you should be aware of
pricing strategies used by most sellers. If you want to build a business this can help you dictate a pricing point for your goods or services and as a consumer this might help you be more responsible in buying.
Both consumers and business owners must know the price of the goods they want to buy or sell. This aims to prevent consumers from being fooled by the naughtiness of shop owners in setting prices as they please. The same is true for shop owners and knowing the price of goods so that they can be more free to set prices to attract customers to shop at their stores. Both have the same thing to know the price of goods even though the benefits are different from the perspective of the buyer and the shop owner themselves.
The three points you convey are more to shop owners because basically they are looking for profit from the products they sell. While the buyer category will only benefit if they buy goods below the standard price because they can get a cheap price based on the amount of the standard price from other shop owners.