You do not have to go through a Spanish estate agent to buy property in Spain (it is not compulsory at all), and because the commissions charged by Estate agents in Spain (either run by spanish or foreigners) are high, it is common in Spain to do private house sale.

If you decide to do a private deal however, it is very important that you have a good, trustworthy lawyer to guide you through the whole process and to take care of the smallprint.

Because direct house sales are quite common in Spain, there are lots of places with listings of property for sale. Local newspapers are a good place to start.

If you are looking for an apartment and know the area where you want to buy, you could also try visiting the apartment blocks you like most and leaving your name and number with the portero, as the caretakers of these complexes are called. They usually know if any apartments in that block are for sale and can point you in the direction of the owners.

If you are looking for a villa, try driving around the residential areas and looking for signs saying "se vende" (for sale). You can usually tell which ones have been put there by an estate agent, and which ones have been put there by the owners.