prudie, officially there is no limit.
however, there is a quantity beyond which you would open yourself to the Spanish Inquisition. for spirits, the figure is 10litres; for cigarettes, the figure is 800. if you have more than the quoted figure, and if the customs guys don't believe your story, goods can be seized.
if you've been to Andorra, quite often there will only be a cursory check of your car at the border. the full search is then sprung on you an hour down the road. :-0