Prices vary little between suppliers, about €1 at present. Alas, Repsol and Cepsa all have little tankers to visit fincas. We use Cepsa on 977.504.481. I think that 250L is about the minimum they want to deliver and they only take cash. You may need to meet them somewhere and guide them in first time round. After that they will know who you are and find you. The guy who delivers to us and the guy on the phone have enough English to let you place an order.