Milan has a very efficient public transportation, with 5 metro lines and several trams and coaches, operated by ATM. 

Urban Ticket
Price: € 2.00
Validity: 90 minutes after stamping. Valid for a single journey on the underground or rail network, including the urban rail lines of Trenord and the 'Passante Ferroviario' (Urban Railway Network).

Carnet of 10 Standard Tickets
Price: € 18.00
Validity: 10 journeys 90 minutes each after stamping. Each ticket is valid for a single journey on the underground or rail network, including the urban rail lines of Trenord and the 'Passante Ferroviario' (Urban Railway Network). May not be used simultaneously by more than one passenger.

One Day Ticket
Price: € 7.00
Validity: 24 hours after stamping.

Three Day Ticket
Price: € 12.00
Validity: 72 hours after stamping.

 

To travel regularly in Milan urban area. Urban Travel Card allows you to use all the urban ATM network with the urban leg of the intercity routes, and the urban rail lines of Trenord and the 'Passante Ferroviario' (Urban Railway Network).

To purchase the travel card of your choice you need to request an Electronic Card for Students that costs € 10 and is valid for 4 years.
 

Monthly Travel Card for Day Students
Price: € 22.00  monthly recharge for under 26 yo otherwise € 39.00
Validity: 1 solar month (in other words from the 1st to the last day of the month for which the travel card was purchased): valid for unlimited journeys during the month of validity.

 

More information: https://www.atm.it/en/ViaggiaConNoi/Biglietti/Pages/Tipologie.aspx

The metro service starts around 5:30 and ends around 00:30. During the night the Metro service is not active, but there are Replacement Buses.