I have a nice appartment in Barcelona. It's very conveniently located close to Sants railway station. It's just 10 minutes to the centre of the city with the undeground tube.
There's WiFi available for you.
The flat has two bedrooms and you will be staying in the big one with a big bed for one or two people. The bed can perfectly accomodate two people.
This is perfect place for a single person or a couple. And the room is much nicer and cheaper than any hostel in Barcelona.
I expect you to be tidy and respectful with the neighbours