Have you ever though about renting a room for a few nights? Itīs much cheaper and more fun as you will stay with locals. On www.loquo.com
you can find a big collection.
Not sure when you are coming, but from time to time I rent out a room as well. We only share the bathroom and kitchen, the house is nicely decorated and clean. And much cheaper than a hotel!
When you are interested, please send me a mail via firstname.lastname@example.org.
or for the roomshttp://roomsforrentinbarcelona.blogspot.com/