Actually one can shop everywhere in Barcelona. This town knows hardly any separation between living and shopping. This is also a reason that there is everywhere lively life in this town. Everything is actually everywhere available and is used whether household goods, food, clothes, restaurants and bars.
For everyone do not know Barcelona so well, it gives a so-called shopping line. This Line leads from the Rambla, crosses Plaza Catalunya and ends at the Paseo de Gracia. One can walk the complete way well.