Public Transportation

Prague public transportation (MHD)

Prague has an excellent public transportation system (MHD in Czech). There are trams (streetcars), busses and the metro (subway). They all use the same tickets which can be purchased in the metro stations, in some shops, some hotels, etc. They cannot be purchased in the tram, bus or subway car. Follow English instructions on the ticket. There are some "night trams" which run only at night. Please make sure you validate your ticket as you enter the metro station or tram. These yellow machines are located on posts as you enter. An invalidated ticket is the same as no ticket and if checked by the metro personnel, there is a large penalty payable on the spot. One enters the metro area, tram or bus without having his/her ticket checked, however, the MHD personnell do routine checks often!
For more detailed information, please visit the official site of the Prague Integrated Public Transportation System

Below is a simple map of the metro system, however, all forms of maps are available on the official website above.

From the airport into the city center by public transportation:

To get from the airport to town the cheapest way:
Coming out of customs at Prague Ruzyne airport .... look right in the hall.  Almost in front of the stairs is a booth selling tickets for public transportation.  Purchase your tickets for each way and person in the arrival hall of the Prague Airport.  They will also have the currect prices and directions to your final destination. 
If you don't have Czech money, there are ATMs/bankmachines are located in the arrivals halls.  There are stands in the arrivals hall of both terminals which will sell you these tickets along with giving you a free map of the metro system.