It depends for what reasons you are considering buying the property wen?
1) What is the bank value of the property?
2) How much is it offered to you at?
3) Are you planning to re-sell it straight away or within a few years?
4) Will you need a mortgage to purchase it?
5) Are you planning to rent it out?
Remember the market conditions suggest that there could be a further decline in property prices over the next 18 months. I predict at least 20-25%.
If you are buying in sterling, then with the current exchange rate at €1.27 = 1 GBP, you will have to find about 15% more than before Xmas to cover the lower exchange rate.
So the property could drop in value by 25% plus you need 15% to cover exchange rate plus 10% purchase costs. So even if the property is for sale at 40% below bank valuation, it could be several years before you can sell it and see a profit.
Remember wen, wise investors are not buying property in Spain at present, or in any country to be exact. They are not buying even at 40% below bank valuation.
It would really need to be 50% less than bank val before it was a real bargain, even then you would not see any real profit for a couple of years at least.