There are a wide variety of these policies, any of which can have an impact upon international trade. For example, income taxes are levied on wage and capital income of individuals. Profit taxes are levied on the profits of businesses. Sales taxes are generally levied as a percentage of retail sales. In the US these taxes are popular within individual states.
Excise taxes are specific taxes on particular commodities such as gasoline, alcohol or cigarettes.
Some domestic government policies take the form of quantity restrictions. An example is controls on the amount of pollutants that industries can emit. Also, in most countries there are restrictions on the production and sale of many drugs. The US prohibits the use of recreational drugs like marijuana and cocaine, as well as pharmaceuticals that have not been approved by the Food and Drug Administration. Governments also provide subsidies for many purposes.