Mercantilism was good for the british because they could get their good and raw material and it back to the colonies

Mercantilism was good for the British because they could get their good and raw material and sell it back to the colonies.

Not everyone agreed that mercantilism was good for the home country, incidentally.  Economic theorist Adam Smith criticized what he called the "mercantile system" because it restricted trade and thus restricted economic growth.  The mercantile system believed the wealth of the world was a fixed amount, measured primarily in gold and silver accumulated.  The system promoted a nation selling its products abroad but not needing to buy from others, or imposing heavy tariffs if importing anything.  And as your question pointed out, it used colonies as sources of raw materials and clients for finished goods.  Commerce was heavily controlled by the government through charters granted to specific trading companies.
Smith countered mercantilist ideas by advocating a free market -- the opportunity for all nations to increase their wealth by exchanging goods freely with one another according to what would become known as capitalist principles.