Here is a previous question that has some answers
http://travellr.com/questions/spain/259/what-are-some-good-places-to-stay-in-or-around-barcelona almost 10 years ago
there are lots of hotels in Barcelona.
Have a look at Banys Orientals (http://www.hotelbanysorientals.com/). It's right in the Born district, where you can find lots of tapas places, many shops and a lot of history (museums, churches...). It's not such a big hotel, but it's worth a visit.
Other fashionable hotels I like (it always depends on what you consider expensive):
Hotel Omm: http://www.hotelomm.es/ (from 150 per night)
Hotel Princess: http://www.hotelbarcelonaprincess.com/es/hotel.php (from 120 per night)
Hotel Silken: http://www.hoteles-silken.com/hotel-diagonal-barcelona/ (from 100 Eur)
Hotel Olivia Plaza: http://www.oliviahotels.es/es/index.php (from 140 Eur)
Hotel Alexandra: http://www.epoquehotels.com/h.php/barcelona-hotels/boutique-hotel/h/alexandrabcnhotel/l/es (from 89 Eur)
Hotel Chic&Basic: http://www.chicandbasic.com/ (from 95 Eur)
I hope you have a good time here. almost 10 years ago
Maybe a bit late but for the people who still need it:
Daily Flats Cheap accommodation hotels and apartments (located in Barcelona)
They now have a promo where you can get -5% on your booking if you use this code DS-T7SQX
Have fun on the trip! about 9 years ago