Which is the best value for money? a 300ml bottle of shower gel priced £2.25 or a 125ml bottle of shower gel priced 90p?

In order to answer this question, you need to work out the price per ml. 300ml bottle: 2.25/300 = £0.0075 per ml 125ml bottle: 0.9/125 = £0.0072 per ml. Therefore, the 125ml bottle is better value for money.