for the crisps, for every 3 packets one is free. as you want 6 packets, 2 will be free. so 4 x 1.43 = £5.72
for the fig rolls, if you buy two one will be half price. as we want three, 2 will be normal price and 1 will be half price. 1.08 + 1.08 + 0.54 = £2.70
