Is it better to buy the 6-pack at £10.49, or the 8-pack at 14.99?How about a choice between 6 pints of milk at £2.19 and 4 Litres at £2.33?Or is 12 x 300ml beer pack for £10.00 better value than the 6 pints at £8.00?Although the supermarkets often list comparison prices as cost/100ml, cost/100g, etc, it is still not easy for most to visualise what that means in terms of the cost differences between the actual products being chosen between.That