Quantity Discount : 28.75% to 36.25% off 5+ @ 28.75% : 135.86 + 24.45 (18%) = 160.31 10+ @ 32.50% : 128.71 + 23.17 (18%) = 151.88 15+ @ 36.25% : 121.56 + 21.88 (18%) = 143.44