It is best to rent a car with a full insurance, as this will save time and money if you are involved in an accident. If you must hail a taxi on the street, be sure that the name of the taxi company is clearly marked on it. Insist on using the meter. Don't fall for a driver who bargains or claims that his meter is broken and make sure the taxi driver re-sets the meter before you start your journey. Take plenty of change with you.
Many drivers never seem to carry enough.
This may come handy if you want to register a complaint or trace belongings left behind. There are licensed taxis at Bali's airport. Avoid taking services from 'brokers' who offer you transportation. There is plenty of other private transport on offer but you need to negotiate the price. In places such as Ubud, Sanur and Kuta there are many people who offer you transportation services.