It is quite hard to give anything more than a rough guide to the cost of living in Spain. Prices vary greatly by area, with the cost of living much higher in the urban centers such as Madrid and Barcelona than in the rural Spanish villages and towns.
In the Spanish urban centers, the price of housing is high relative to the other costs of living. Spaniards who did not buy housing when prices were lower now find it necessary to pay more than half the average income to get average housing, which is a very high percentage. On the other hand, a good cup of café con leche can be had in many cafes in Spain for a Euro or less, and the cost of fruit and vegetables can be a bargain. As a consequence, many Spaniards in the big Spanish cities live packed into quite small apartments and observe a social life centered in cafes and restaurants rather than their homes.
Since the introduction of the Euro, there has been a perceived inflation in prices in Spain. With the conversion, some prices were rounded up to the nearest Euro equivalent, with more increases coming in time.
With all those caveats, here are some very rough costs for you that can be used for gauging the cost of living.
Electricity: For two people bills are around 30 to 35 euros per month.
Telephone: Flat-fee of about 20 euros per month with the calls that you make on top of that.
Food: For two people bills are generally 300 Euros a month. An average restaurant bill is eight to fifteen Euros (much cheaper at lunch), with a glass of beer or wine one to two Euros.
Cinema: Around five to six Euros to see a movie.
Schooling: Public schools in Spain are often Catholic parochial schools supported by the state. Charges are nominal.