A friend just put me onto one more organization you might want to contact. Servas (www.servas.org) is an international organization. If you are 18 or older, you can apply to be a traveller or a host. Pass muster (I think you are interviewed), you can stay in private homes for 2 nights at a time at no charge (is that cheap enough?). The hope is that you'll also register as a host, and offer the same hospitality to other travellers.

Having stayed in B&B's on occasion overseas, there are wonderful advantages to staying with a private or semi-private home, along with a few drawbacks.

It's an old and well-respected organization. The web site is a little clunky and takes some patience, but there is some good information there (and they do have sites in Spain!).

JP