Two taxis, arrive and depart is 120 euros, we hired a VW polo for the week, they meet you and you return you to the airport, sat nav included, total cost approx 180 euros/week.
This enabled us to have days out and we and found and saw some of the lovely villages and scenery for some of our holiday.
It also enabled to visit 2 or 3 lovely restaurants in the surrounding areas that can only be reached by car or taxi, which is not really an option in Arillas.