Good to read : Law Of Demand

• http://www.investopedia.com/terms/l/lawofdemand.asp

DEFINITION of 'Law Of Demand'

A microeconomic law that states, 

all other factors being equal, as the price of a good or service increases, consumer demand for the good or service will decrease, and vice versa. 

The law of demand says that 

the higher the price, the lower the quantity demanded, because consumers’ opportunity cost to acquire that good or service increases, and they must make more tradeoffs to acquire the more expensive product.