Sants is a 10 minute metro ride out of the center of town. It is the main place in Spain for conventions to be held because of the large exhibition hall called the Fira. It is an affordable place to stay and is well connected by public transport. You could walk to gorgeous Plaça Espanya and Montjuïc where there are attractions such as Poble Espanyol, the Magic Fountain and the Fira Barcelona events halls