miemie - it depends on whether you *need* to go to Barcelona, or simply *want* to go to Barcelona. It sounds as if you merely *want* to have a fun time over Easter - and I therefore recommend that you pick the cheapest airline providing passage at times convenient to you and enjoy the long break.
As with almost any airline, and depending on the laws applying to credit cards in the country in which you live, you may wish to use a credit card to purchase the ticket - it normally makes the credit card issuer liable if the airline fails to provide transport.