Price elasticity of demand is a measure of the responsiveness of the quantity of a good demanded to changes in its price. If the demand of a good is largely affected by a change in its price, demand for this good would be referred as price elastic. On the other hand, if the demand of a good is not affected by a change in its price, it would be referred as price inelastic. An example of a good with price inelastic demand would be insulin for diabetics. They will still consume this good even if the price increases because there are not close substitutes and they need it to survive. For other goods, such as milk, if the price increases , consumers will start buying a cheaper milk as a result and demand would be affected.