If I cannot afford a lawyer and one is appointed why would I have to pay if found guilty?

Unless I misunderstood the judge during the reading of his rules regarding pleas and attorneys, he stated that if you plead not guilty and are appointed a lawyer because you cannot afford one, you will be required to pay the lawyer if you are found guilty. This does not sound ethical in opinion. The state is North Carolina. Please give me some feedback and explanation. It is the judicial branch that interprets the law, so who and when did this occur?