Barcelona has hundreds of places to sleep in all shapes and styles, from glamorous boutique lodgings to middle of the road boutique lodgings to boutique B&Bs and boutique hostales (or pensions—don't confuse them with youth hostels, although some do offer dormitory style rooms). There are even a few left that do not aspire to boutique-dom.
In fact, as in the rest of Spain, they built too much during the boom times, which is good news for visitors during the current economic squeeze and reflected in the prices—at least below the five star luxury level, where prices can still be fairly breathtaking: rooms at the Arts can be well over a €1000 a night.
But even up in the stratosphere you may find good discounts—on the hotels' own websites, or from the Barcelona Hotel Association which lists over 250 hotels and apartments (book on line, with a credit card) or from the web: Expedia or Booking.com or lastminute.com, among many.
Image by urban_data