Barcelona Accomodations On A Budget But Near The Action

You might want to explore the option of an apartment. I just checked the Friendly Rentals site ( where I am renting for the fall) and there are a number of apartments that sleep 4 for around 500 euros for four nights - a couple even less expensive. There are many other rental agencies in Barcelona and renting an apartment may be cheaper than the other options you listed. If you do a little research you can discover the area which will best suit your needs and choose an apartment accordingly.
You also save money in an apartment because you can have breakfast and a few other meals in the apartment.

I rented a 2 bedroom apartment in Barcelona that is near Sagrada Familia. It is not near great bars and restaurants as you have requested, but worth considering if you find a more central place less affordable. We paid 95€ per night last September. Check out VRBO #74574. You have less than a month to find something during peak season, so you should try to book something ASAP.

You might look into the Hosteria Grau. It looks like they have two family rooms that will hold 4 people and they also have very inexpensive rooms for singles that have a shared bath (38Euro). It's in the Rick Steve's book. It's also very near La Rambla and several of those great tapas bars. http://www.hostalgrau.com/en/hotel-overview.html

I was pretty happy with Hostel Campi. About half the rooms have ensuite and half use the bathrooms down the hall. Our room was the latter. For the money it was a reasonable size room, good staff, really convenient location (a block off the Rambla, two blocks from Placa Catalunya). It wasn't fancy but it was clean and quiet, which is what I care about. I did request a "tranquil" room and got one on the interior side rather than overlooking a street (which might be louder).