Resources spent in carrying out activities; also, the benefits sacrificed through choosing a particular of course of action over another.

- Opportunity costs: the value of benefits foregone by failure to apply the resources to the most productive alternative cost.
- Marginal costs: the extra cost of increasing output by one unit.
- Variable costs: costs that vary with changes in output volume, such as materials required to provide a service.
- Fixed costs: costs that do not vary with quantity or volume of output provided, at least in the short run (e.g., rent).
- Resource costs: resources used in the production of goods and services.
- User cost: cost to the user to purchase or make use of a product.

Direct cost: all the goods, services, and other resources that are consumed in the provision of a particular service or area (e.g., hospital supplies), including medical costs (e.g., payments to providers, materials) and non-medical costs (e.g., delivery).

Indirect cost: total sum of morbidity costs (goods and services not produced by the patient because of the illness), mortality costs (goods and services the person could have produced had the illness not been incurred and the person not died prematurely), and productivity cost (related to lost productivity incurred by an employee who leaves work to provide care for the patient).
Intangible costs: usually used in economic evaluation, to indicate features like pain, anxiety, or grief, which cannot be directly quantified in monetary terms.

World Health Organization. European Observatory on Health Systems and Policies. Glossary. 2009.