Free goods are goods that are available in quantities greater than people want at a particular place and time. Because they are not scarce, using them has zero opportunity cost and no price is needed to ration them.
This is common SL and HL content in Unit 1.1: What is economics?
Economics begins with scarcity: resources are limited relative to unlimited human needs and wants. Most goods are therefore economic goods, meaning that producing or consuming them requires a sacrifice of the next best alternative.
A free good is different. If sunlight is freely available and one person's use does not prevent anyone else from obtaining the sunlight they want, no alternative must be forgone. Its opportunity cost is therefore zero.
| Type of good | Defining feature | Example |
|---|---|---|
| Free good | Not scarce; zero opportunity cost | Sunlight in normal conditions |
| Economic good | Scarce; has an opportunity cost | Food, housing or electricity |
| Public good | Non-rivalrous and non-excludable | National defence |
Whether something is a free good depends on context. Air may normally be treated as a free good, but clean air becomes scarce where pollution reduces its availability. Bottled oxygen also requires resources to produce and distribute, so it is an economic good.
A common misconception is that a free good is simply something with a market price of zero. This is incorrect. Free healthcare or education still uses scarce labour, capital and government funding, so it has an opportunity cost even when consumers pay no direct price. Free goods must also not be confused with public goods, which are defined by non-rivalry and non-excludability, not by zero opportunity cost.
Exam technique: For a definition question, state both essential features: a free good is not scarce relative to wants and has zero opportunity cost. For an explanation, add a contextual example and explain why no alternative is forgone.