If you are looking for a relatively inexpensive City Break and are flying from Dublin Airport, check out Madrid. Both Aer Lingus and Ryanair fly there and the flight time is short so you can make the most of your time away. Both carriers have competively priced flights so check both when booking. We actually flew out with Aer Lingus and back with Ryanair when we spent 4 days in Madrid in December 2014. This meant we got the flight prices and times that suited us best.