How much do things cost in Barcelona and Cardiff? Cardiff is 25% more expensive than Barcelona Cardiff Barcelona Petrol (1 litre)£1.35£1.16 Coke/Pepsi (0.33 litre)£1.01£1.29 Imported beer (0.33 litre)£3.00£2.37 Meal at McDonald's or similar£5.00£5.54 Last updated on 21/07/2014 source