Most places sell these for about £3 for 6 cans but Tesco do 8 cans for £3.05. But Tesco are also currently doing 3 for 2 on a range of ethnic foods making it £6.10 for 24 cans or 25.4p/can.
Unfortunately, for me at least, they don’t seem to stock the diet version. Stacks left at Brent Cross.
3/£1 (33p/ea) @ Asda
6/£3.05 (51p/ea) @ Sainsburys