Since there is no public transportation in Bali, your will need a bike or a car. You can rent both without any problems. If you are not planning to make many long-distance trips, renting a bike would be a more feasible option. For example, with a bike you will be able to avoid traffic which can be overloaded. To rent an average good quality bike (Honda Vario or Honda Scoopy) costs 700,000 rupees on average. This is very inexpensive in comparison to, say, Thailand. A liter of petrol costs around $0.5. To rent a car or a bike only a copy of your passport is needed.