This Bangkok scam can occur anywhere in Thailand but it usually occurs at the airport. Drivers will ask where you want to go and just throw out a random figure, such as 500 baht or 1000 baht. However if they used the meter the ride would be a whole lot cheaper.
500 baht or 15 or 20 dollars is nothing for most Americans for a Taxi ride but the regular price would probably be 200 baht or less, so they are making a lot of money scamming you.
- See more at: http://www.bangkokbeyond.com/blog/bangkok-scams#sthash.aCrWmmxz.dpuf