This person is a troll, my god 25 zl from airport to centrum, perhaps he meant that 3 people shared the taxi and paid 25zl each.
Well, let's see, the legal daytime maximum for a taxi in Warsaw is currently 3zl per kilometre (although no corporation charges that much, the maximum real rate is 2.40zl/km and is charged by all the three corporations permitted to operate from Warsaw airport). Warsaw airport is 10km south of the city centre. So with the 6zl for the first kilometre, the maximum legal daytime charge to city centre would be 33zl.
At night and during sundays/holidays, the maximum rate is 4.50zl/km but the first Kilometre rate is the same. So that's a maximum of 46.5zl.
If you are asked for 75zl to get from the airport to the city centre, you are being robbed. Get your camera out and get a photo of the driver and his ID card (which should be on display in the cab). Then ask for a receipt which says where from and where to. Once you do this, cabbies suddenly get a lot more reasonable and will most probably put your fare to the level it should be at.
Make sure your taxi has a sign saying "TAXI" on the roof and not "TAKI" or "TAX1" as you will sometimes see.
Oh, and one more thing: never argue the fare too much. If the driver insists you will pay an amount, you will pay that much and he'll be happy to get six of his mates to come and explain why you should pay the fare. Just get receipt plus photo of driver and cab number (on the door) and license plate. That should be enough to file a formal complaint.
Are taxis charging by the person they drive, or is the price the same for one, two or three? (puzzled)
The price is the same for one to four people. Above that different rules apply because the cab needs a slightly different license.