I think you definitely have the right idea in looking to buy an established business if you can. As I am sure you know from your UK experience, it takes years, not months, to build a business and start really earning from it, so how much harder when you also have to deal with a completely new system, not to mention a language.
When faced with what looks like a big price for a small business, consider how much it might cost to set something up (including initial promotional costs etc, not just the rent and fittings and stock) and to run it for at least two years before you make a profit. Assuming you can establish the real level of profitability through proper due diligence, you will probably find it is cheaper (and certainly less stressful) than setting up on your own.
However, if you can't find a business you fancy running and you want to plough your own furrow, think about investing some serious time and effort in research. Choose an area, go and live there (preferably renting unless you find a real bargain property) and thoroughly research the gaps in the market. Develop a circle of friends and you will discover what is lacking in the area. If you want to succeed with a new venture you have to avoid the type of business which has lots of established competition. I wish I had just €100 for every business I have seen set up in the last seven years in our part of Spain which were doomed to failure from the outset. There really is no substitute for thorough research and hard work, and spending time in an area will help you make the contacts which will tell you which businesses are really successful and which are probably on their last legs. We all know, for example, of locations which have had three or four incarnations under different management in almost as many years (the triumph of hope over experience) and seem to have some sort of jinx.
Finally, unless you are buying an established business and the owners are willing to work side by side with you for a few months, it really is advisable to stick with something of which you have some experience. I never cease to be amazed by the number of people who come and open the kind of business of which they have no experience at all, and then are surprised when it fails. You would surely not open a pub in England if you had no experience at all of bar work but the costas are littered with the broken dreams of literally hundreds who have done just that.
Sorry to be so long-winded but I hope this is helpful. While writing I can thoroughly recommend eastern Almeria, but then I am prejudiced! The economy is still growing and there are definitely opportunities for people willing to work.