Thanks to the practice of mercantilism, England controlled trade in a way that allowed them to export more goods than they imported. South Carolina was both a source of raw materials and also a market for British manufactured goods. This allowed England to become less dependent on foreign trade with countries such as China and improved the balance of trade in favour of England.
By English law, rice and Indigo were sold solely to England, however, the English did not enforce this law, opening up the marktplace for rice. This gave South Carolina a secure market in England and a wider market in the world.