How to stay in Barcelona for $8 a night

I seemed to have stumbled onto a very fortunate living arrangement.
Jen and I really wanted to learn spanish while we were in Barcelona. We found a offer for a 3 week spanish class (run by a company called Don Quiote) through the lake tahoe community college. Being california residents we ended up paying the in state tutition of $72 per person for the course plus living arrangements provided by the school.

The living arrangements were a double bed private room in an apartment on the Gran Via in Barcelona. Total cost was $210 for the both of us for 3 weeks.
However, after a measly 3 hours of the classes I decided that I really didn’t want to spend my vacation stuck inside a classroom wishing to be exploring the city, so I just didn’t go back.
So now the situation is that jen and I have all day to explore the city and a private room at night. All for $8 a night!
The math:
Tutition: $3 per day ($72 total)
Apartment (through Don Quiote): $5 per person, per night
Total:$8 per day!
Now if I just could find a computer that has a USB port…