Section 8. All such in-lots and out-lots, rated number one, shall pay the original purchase money and full interest; all rated number two, shall pay the original purchase money and four and an half per cent interest; all rated number three, shall pay the original purchase money and three per cent interest, and all rated number four, shall pay no interest and patents shall issue for said lots, on paying as aforesaid, with the patenting fees as now required by law for town lots.