Barcelona is one of the most popular cities in the world, and many people who come for a few months end up staying longer, sometimes even indefinitely.
The biggest expense you will face in Barcelona will undoubtedly be that for your accommodation, usually in the form of an apartment. Rental prices typically range between 800 and 2000+ Euro per month, to which you will also need to add the utility bills. You can read more about renting in my guide to renting an apartment in Barcelona.

Barcelona Avinguda Diagonal