1 UNIT £30.99 (including postage and barcode)
2 UNITS £52.48 (including postage and barcode)
3 UNITS £78.72 (including postage, barcode and one free = 4 units)
4 UNITS £104.96 (including postage, barcode and two free = 6 units)
5 UNITS £131.20 (including postage, barcode and three free = 8 units)
6 UNITS £157.44 (including postage, barcode and four free = 10 units)