In consumer theory, an inferior good is a good that decreases in demand when the consumer’s income falls. Inferiority, in this sense, is an observable fact relating to affordability rather than a statement about the quality of the good.
Examples of Inferior Goods: Inter-city bus service is an example of an inferior good. This form of transportation is cheaper than air or rail travel, but is more time-consuming. When money is constricted, traveling by bus becomes more acceptable, but when money is more abundant than time, more rapid transport is preferred. Inexpensive foods like hamburger, frozen dinners, and canned goods are additional examples of inferior goods. As incomes rise, one tends to purchase more expensive foods.
What is a Normal Good?
Normal Goods are those goods for which demand rises when income rises and falls when income falls.
Superior goods make up a larger proportion of consumption as income rises, and as such are a type of normal goods in consumer theory.
Examples of Superior Goods: A superior good might be a luxury which isn't purchased at all below a certain level of income, or have a wide quality distribution, such as wine, and holidays (where the number produced may stay constant with rising wealth, but the level of spending goes up, to secure a better experience.)