The price for a single trip can vary between US$20 and US$40 per person (280,000 to 550,000 IDR) – depending on the company.
Buying a round-trip ticket can be significantly cheaper, so plan your stay, and if not sure, pay some extra to get the option to change the return date purchasing an open ticket.
Generally, Sanur is the most convenient port because it is within easy reach from Seminyak, Kuta, Canggu, and the airport. Boats are departing in the morning, as well as in the afternoon.
Although, leaving from Padang Bai can be better for those staying in the East of Bali, such as Candidasa, Sidemen, Amed.
If you like to travel like the locals (and for a cheaper rate!), you can catch the public ferry departing from Padang Bai. The ticket is around 30,000 IDR (US$2). The catch? It can take up to 1h30 and might not be