Welcome to the forum.

http://www.expatica.com/es/employment/employment_information/How-to-apply-for-a-Spanish-work-permit_14685.html

You only give scant details ie if you speak the language. Are of Spanish decent/Qualified in a skill etc.Even People born here can not find work. The only work worth having really is a job with a contract in order you pay into and get things out of "The System" The average cost of that is about 250 euro a month. Cash in hand jobs are not worth the trouble a lot of it goes on but it is on the decline.You leave yourself open to exploitation The contract also opens up other avenues ie buying a car/Bank loans/Rent property etc.There is a lot of info on the internet have a look at the site above but most will tell your unless you have money behind you do not come here thinking you will slot straight into a job It will not happen unless your uncle owns the company bla bla. Anyway good luck and I hope you find what you are looking for, You have the rest of your life it may be the best move you ever make. 

And always remember mummy will still have your room in the UK ready if it all goes thrupenny bits up

:-/