Tax

====Ad valorem and per unit====
{{Main|Ad valorem tax|Per unit tax}}
An ''ad valorem'' tax is one where the tax base is the value of a good, service, or property. Sales taxes, tariffs, property taxes, inheritance taxes, and value-added taxes are different types of ad valorem tax. An ad valorem tax is typically imposed at the time of a transaction (sales tax or value-added tax (VAT)) but it may be imposed on an annual basis (property tax) or in connection with another significant event (inheritance tax or tariffs).

In contrast to ad valorem taxation is a ''per unit'' tax, where the tax base is the quantity of something, regardless of its price. An [[excise tax]] is an example.