Some cracking deals in Asda for softdrinks at the moment:
Irn Bru - 2 Litre bottle - £1
Coke, Diet Coke or Coke Zero - 15 pack of 330ml cans - £4
Pepsi, Diet Pepsi, Pepsi Max - 18 Pack of 330ml cans - £5
Irn Bru - multipack of 330ml cans - works out at around 26p per can, can't remember the number of cans in a pack.