It is better to avoid getting a taxi at Krakow Balice airport if you arrive or depart between 4 am to Midnight because there is a great , fast , cheap , modern train .
*Shuttle train service links Krakow’s John Paul II International Airport in Balice with the Krakow Glowny main rail station in the city center. On average, trains run every thirty minutes between 4 a.m. and midnight. The 15-kilometer journey lasts about 15 minutes. A single ticket costs an equivalent of roughly 2 euro/ 1£. One can can purchase tickets on the train.
To take the shutlle just wait in front of the international airport and you will see a bus coming to take you 3 mns away ( free) to the train platform.And you can buy the tickets from a machine in the Airport Terminal.
if you really need to take a cab to get to your hotel or accomodation in the center better take it from the main station in Krakow it will be cheaper.
It is always a rip off to take a taxi from the airport and i never got charged the same price! The cheapest fare i paid from the airport was 50zl for a 30 mns ride but at night it is easily 70zl to 80 zl.
I heard there is also a Shuttle bus but it is slower .