When any action ex contractu is brought in the superior or state court and the verdict of the jury, unreduced by setoff or payment pending the action, is for a sum under $50.00, the defendant shall not be charged with more costs than would have necessarily accrued if the case had been heard before a magistrate. The remainder of the court costs shall be paid by the plaintiff and may be retained out of the sum recovered by the plaintiff and, if that is insufficient, judgment shall be entered by the court against the plaintiff for the balance.