Price sensitivity, also known as price elasticity of demand, refers to how consumers' purchasing behavior changes in response to changes in the price of a product or service. Understanding price sensitivity is crucial for businesses to set optimal pricing strategies. There are several "laws" or principles that help describe and predict how consumers react to price changes. Here are nine laws of price sensitivity:

1. Law of Demand:
   The most fundamental law of price sensitivity states that as the price of a product or service increases, the quantity demanded decreases, and vice versa, assuming all other factors remain constant. This inverse relationship between price and demand is represented by a downward-sloping demand curve.

2. Law of Diminishing Marginal Utility:
   This law suggests that as a consumer consumes more units of a product, the additional satisfaction (utility) gained from each additional unit decreases. In terms of price sensitivity, this means that consumers are typically more price-sensitive for the first units of a product than for subsequent units.

3. Income Elasticity of Demand:
   This law focuses on the relationship between changes in consumer income and price sensitivity. If a product is considered a normal good (demand increases as income rises), consumers are less price-sensitive as