By car
Don't bother driving in the city centre. There's often a lot of traffic, parking spaces are scarce and can be expensive, and Polish driving takes a lot of getting used to. There are also rules around local 'driving zones' that confuse even long time residents. The taxis are cheap and it makes more sense to use them.
Taxis, reliable and fair play taxi drivers from the airport or for a longer transfer should be booked in advance by the internet. For instance Krakow airport transfer to Krakow costs around 70PLN. During the day, most fares will be around 20PLN. All taxis should have a 'Taxi' sign on the roof and a sticker on the rear passenger window with prices. There is an initial charge of about 5-7PLN, plus 2-3PLN per kilometre. Price list should be shown on the passenger side door.
Car services such as iCar (http://icarauto.pl) or Car-o (http://www.car-o.pl/) or MaxiDriver (http://maxidriver.pl/) are almost always less expensive than taxis, and will quote you the prices in advance based on the real distance between you and your destination. An 8 km ride will run you about 22 PLN.
There are instances where drivers will overcharge tourists, especially those who don't speak Polish. Check on a map in advance how much it should be and if it goes much above that, debate the price.
