Free and Economic Goods
Definition
Free good: a good so abundant relative to wants that it can be consumed at zero opportunity cost, for example sunlight or air on a remote beach.
Economic good (private good): a scarce good that is rival and excludable, so consuming it carries an opportunity cost, for example a bottle of water bought for £1.
- An economic good is scarce because making it uses up limited factors of production.
- Because those resources could have made something else, consuming the good carries an opportunity cost.
Key Idea
- Scarcity is the single feature that separates free goods from economic goods.
- Only scarce goods use up resources, so only economic goods carry an opportunity cost.
- This is why economics studies the allocation of scarce resources, not free ones.
Rivalry and Excludability
- An economic good is rival in consumption, so one person's use leaves less of the good available for everyone else.
- An economic good is also excludable, so a supplier can stop anyone who does not pay from consuming it.
- Rivalry and excludability together let a market attach a price and ration the good among competing users.
Note
- A good can shift from free to economic once it becomes scarce.
- Clean air is treated as an economic good in places where pollution makes it scarce.
- Being free is about the absence of scarcity, not about having a low price.
A Worked Test
- Ask first whether there is enough of the good to satisfy all wants at a zero price.
- If there is, the good is free and has no opportunity cost.
- If there is not, check whether consuming it uses up scarce resources.
- If it does, the good is an economic good and carries an opportunity cost.
Example
- Consider a litre of bottled water sold in a shop for £1.
- Producing it uses labour, plastic and machinery, which are all scarce.
- Because those resources could have made something else, the water carries an opportunity cost.
- One shopper's bottle cannot be drunk by another, so it is rival, and the shop can refuse non-payers, so it is excludable.
- The same water falling as rain in an unpopulated area is not scarce and would be a free good.
- This shows the label depends on scarcity in a given context, not on the physical substance.
Why Scarcity Creates Price
- Only scarce goods need to be rationed among competing users.
- A market rations a scarce good by charging a price, which rises when the good is scarcer and raises the incentive to supply more.
- A free good needs no price, because there is enough for everyone.
Exam technique
- Define a free good by its lack of scarcity and its zero opportunity cost.
- Define an economic good by scarcity, rivalry and excludability.
- State all three features to secure the knowledge marks.
- Support the distinction with a clear contrast, such as air versus bottled water.
Common Mistake
- Do not call a good free just because its price is low.
- A free good has no opportunity cost at all, not merely a small one.
- Do not assume a good is permanently free or permanently economic.
- The same good can become scarce and then command a price.
Self review
- Define a free good and an economic good.
- State the two features that make a private good tradable in a market.
- Give one example of each type of good.
- Explain why economic goods have a price but free goods do not.
- Explain how a free good can become an economic good.
