Do I need to buy a ticket before getting on?
'Salire' — stress the first syllable: SA-li-re. The final 'e' is pronounced.
Ask this when you are unsure whether to buy before entering or whether there is a conductor on board. On Italian metro systems, you always need a validated ticket before passing the turnstile.
'Fare il biglietto' is a colloquial phrase meaning to buy or get a ticket. Literally 'fare' means to make or do, but in this context it means to purchase. 'Prima di + infinitive' means before doing something — a very useful construction.
Posso comprare il biglietto a bordo?
Can I buy a ticket on board?
On metro systems the answer is always no; on some regional trains yes.
Dove si compra il biglietto?
Where do you buy the ticket?
Good starting question when you cannot find the machine.
La macchinetta accetta banconote?
Does the machine accept banknotes?
Ticket machines often only take coins or cards.
Travelling without a validated ticket is called 'viaggiare in nero' (travelling in black) in Italian slang. Inspectors (controllori) can board at any time and fines are issued on the spot. Tourists are not exempt.