It is done by having Member States agree to common economic policies surrounding the movement of the factors of economy.
This is a good thing, since Member States will have increased movement for their products. However, it also means that such environments are highly competitive, and a lot of companies can suffer great loss if they cannot keep up with the challenges of the competition. It is also very difficult to form a monopoly, and that is a good thing, because the consumers get the best value for the products at lower cost because a lot of companies compete to get the attention of the consumers, rather than having just one company dictating the price for maximum profit and having no choice for the customers of which products to use.
Products and services are also given the chance to reach the places where they are most valued, without additional barriers, reaching their maximum efficiency. It is mainly achieved by prohibition. Article 25 EC (cited in Weatherill, S 2007, “Cases and Materials on EU Law” p. 319) states that “Customs duties on imports and exports and charges having equivalent effect shall be prohibited between Member States. This prohibition shall also apply to customs duties of a fiscal nature.”
There is no “customs control at the borders of Member States” (Four Freedoms (European Union), viewed 23 April, 2010), but rather, the “Physical controls of imports and exports now occur at the trader’s premises” (Four Freedoms (European Union), viewed 23 April, 2010).
Furthermore, Article 90 (cited in Weatherill, S 2007, p.319) shows that “No member State shall impose, directly or indirectly, on the products of other Member States any internal taxation of any kind in excess of that imposed directly or indirectly on similar domestic products.”
It consists of prohibitions imposed on Member States of