Well, you should be in an average rating, something between 2 million and 5 million pesetas/year (it depends on how good you are and other factors). As reference, a high executive would earn between 12 and 20 millions, and a McDonalds employee 1 or 1,5 millions.
Apart from that there are two extra payings (in July and in December), between 15 and 30 days of vacation in summer. National employees are afiliated to the Health Insurance System. That means that if you need medical assistance you have it "for free" (you pay a certain amount of your wages every month).
Also, if they fire you, the have legally to compensate you with a certain quantity, which depends proportionaly on how much you earn and how long have you been working for that company.
Moreover, when you reach 65 years-old you stop working and you have a monthly income which depends on how much you have been earning and how long you have been working (this service is included in what the state keeps monthly from your income).
Hope this helps...
Fernando