Do you have a ticket to sell me?
'Biglietto' — 'bi-LYET-to'. The 'gli' sound is like the 'll' in 'million', not a hard 'g'.
Use this when the nearby tabaccheria is closed and you need a ticket urgently. Some locals carry spare tickets and may sell one.
'Ha' is the formal 'lei' form of 'avere'. 'Da vendermi' is an infinitive phrase meaning 'to sell me', using the indirect pronoun 'mi' attached to the infinitive. This is a slightly old-fashioned but perfectly correct structure.
Dove posso comprare un biglietto?
Where can I buy a ticket?
General question useful at any stop.
Si può fare il biglietto sull'autobus?
Can you buy a ticket on the bus?
Impersonal 'si' construction; very common in Italian.
C'è una tabaccheria qui vicino?
Is there a tobacconist nearby?
Most Italian bus tickets are sold at tabaccherie.
In Italy you almost never buy bus tickets on board — they must be purchased beforehand at a tabaccheria, edicola (newsstand), or automatic machine. Boarding without a validated ticket risks a fine of €50–€100.