If you do not want to spend much money on lunches and dinners in Barcelona, take a look at Romesko restaurant, named after the famous sauce, which is usually fed to the onions kalsots.
In Romesko serves classic Catalan and Spanish dishes at very low prices, in addition, it is fast and quality service and the restaurant is located in the heart of Barcelona, just a stone's throw from the Ramblas.
All dishes are delicious, cooked on homemade recipes, products, selected good quality. Make tuna grilled artichokes, rabbit, lamb stew, frikando veal, cod or squid. Thursdays are prepared paella.
If you are looking for a nice restaurant with a design and light vegetarian cuisine, the restaurant Romesko you would not like it, everything is simple and without any extra fine. It is not particularly well understood in English. But if you want to close, and inexpensive lunch in a simple establishment with a typical Spanish atmosphere, then this is exactly the place you'll be pleased. The average price of food around 5 €.