Which bit of the tree do you want to cut ?  Twigs, branches, trunk ?  If you're talking firewood you'll want a chainsaw for the logs.  Log splitters (electric or petrol) are expensive for the amounts you're likely to want to split.  Best to cut your log rounds when the wood is green and then split if necessary with a maul when dry.  Probably the best place for chainsaws (I stand to be corrected) is the Husqvana dealer in Tortosa.  They sell Oleo Mac as well.  You'll get good backup there.  Mauls can be bought in most Ferriterias.
P.S.  If you can afford it, get a Stihl chainsaw.  Main dealer is Primitivo Conesa in Jesus.