These dwellings are usually in a terrace, or semi-detached, with little patches of gardens or a balcony and your view is usually scrubbed dusty fields. There is nowhere to walk to, no community, none of the very things that makes Spanish life so unique. You will pay something like 16 million pesetas and up. Buy something in town that gives you the same space or more and you could be spending just 12 Million pesetas. Get the language, this is essential.
Few people speak English and in Jerez and Cadiz the accent is much stronger than Madrid.
The local Spanish owner can get away with murder. You the foreigner will be watched, talked about, informed upon, especially if you have bought in a cheap area. Learning Spanish before you come will prevent many problems and they will warm to you and help you so much more if you make the effort. Getting to Jerez. Fly to Madrid or Sevilla, catch the AVE train or Andalucian Express.