One of the most common scams where the tourists end up paying a higher price includes denominations. In Bali currency, the Indonesian Rupiah, there are too many zeroes that might confuse you. You should always remember that $1 (USD) is equivalent to 12,000 IDR. Calculate your conversions based on this simple ratio to figure out how much you need to pay. If you are confused, take help, else you will be duped for sure. There have been cases where tourists have paid $30 instead of $3 due to the denomination confusions. Consider denominations to be sacred.
The sole source of public transport in Bali is the cab service. There are the blue colour cabs, and then there are blue bird cabs. Always look out for blue bird cabs for the perfect pricing and service. Before getting into the cab, scream meter into the Bali driver's ears so that he turns on the meter. If they refuse to do so, don't get into those cabs. Don't worry; you will surely get the next cab in 30 seconds. You may feel that the charges, without meter, are low. But, the fact is taxi services in Bali are cheap, but the amount that you end up paying without turning on the meter could be loot.
Just when you are done clearing immigration and checking visa details at Bali airport, there will be porters who would be ready to serve you by carrying your bags. They would be waiting at the baggage counter, and will plunge in and pick your bags up before you would do it. They will carry the bags, and charge you for the same. If you want to avoid this scam, take your bags from them, and refuse the service. If you don't, you will end up paying unnecessary amount at the airport.
This one's for the tourists who love to rely on their own vehicle. Picking up a vehicle and riding it in Bali means troubles from police. The Balinese police are known to pullover tourists, who are otherwise doing fine, to gain easy access to tickets and fines. The most common scam sentence includes "you will need to pay out more if you visit the police station". Avoid this scam by carrying a helmet and carrying your international driver permit alongside.
This scam is included in the list of big businesses of Bali. You can easily spot a money changer across any street; the board outside will read the exchange rate signs. There are the regular ones, and then there are the ones who commit frauds. How would you recognize the frauds? Simple, if they offer you rates that are too good, avoid visiting them. Check the money you will receive on your calculator, and if you are getting anything different, avoid getting money from such money changers.