Choose correct date
From Poland to Barcelona Polish people can travel by plane, using cheap airline carriers. But during the hot season, in July and August, prices of tickets can be even 70% more expensive then in another months. That is why you should reserve your flight for June or September, it is still very warm term, but less tourists are interested in it. Those months are also cheaper when you are looking for accommodation. The nicest option in Barcelona are hostels, most of it situated in the middle of the city. If you like to be spontaneous you can look for last minute offers for Spain, but it is a bit risky.
Even though most of the days you will spend on a beach, you have to spare some time on sightseeing. Barcelona is known for phenomenal architecture of Antonio Gaudi, the best example is unfinished Sagrada Familia, catholic cathedral. It is interesting mix of Gothic and Catalonian style, like most of Gaudi’s pieces it walls are decorated with colorful shells and rocks. Next nice masterpiece of this architect is Casa Mila, very odd mansion in shape of an ocean waves. If you prefer more conventional sacral art, visit Saint Eulalia Cathedral, amazing Gothic temple. For more medieval pieces go to Bai Gotic, very old district of Barcelona, filled with small mansions and narrow streets made of stone.
Spain has plenty of great painters in it history, so in Barcelona you can admire their work in various galleries. There are entire Museum dedicated to Pablo Picasso, you will see there pieces from Blue, Pink and latest periods of his art. Another great place is National Museum of Catalonia, where you can see local art from the each style and époque. People who admire modern art will be glad to see Joan Miro House, huge exhibition of this amazing, abstract artist.
Beaches and entertainment
If you prefer to spend each day at the beach you should book a hotel in Girona, not Barcelona.
City is located closest to the tourist area, and you can still visit Barcelona, using bus as mode of transportation. But even from the center of Gaudi’s city you can drive about half an hour to reach closest beach. City ones are not as comfortable as those for travelers, but sea is warm and sand is clean.