Actually Doug, of the homebrew providers that are in Spain, this web is the most economic:
http://www.calarenys.com/
Their grain is reasonably good and in general they are a little bit cheaper than the other webs. If you want dry malt extract at wholesale prices, however, you have to find the official suppliers of brands like Munton's in Spain.
The cheapest I found was a Munton's malt extract supplier in Barcelona. If you get in contact with
pchumillas@indukern.es, you can get 25 kilos of light malt extract for 80 euro. There's a catch though: the minimum order you can make is 75 kilos, so make sure that you have a lot of time for brewing for the next year or so. I would guess with 75 kilos you could make 15 batches of 5 gallons no problem, or 750 beers thereabouts.
Munton's by the way is a great extract. Just finished two 5-gallon batches combining muntons extract with steeped grains from calarenys, and the beer is godlike.