We need foreign currency when traveling abroad and we have been exchanging currency in many ways - first with the local bank or the local money changer, in the local airport's money changer, in the foreign airport's money changer, etc. Based on our experience, the best means of obtaining foreign currency is to withdraw from the foreign ATM using my credit card. The billing at home showed that the mark-up is minimal and it is even an advantage compared to changing US dollars in the foreign money changer or in the airport. Except for Singapore where the money changers have the best rates (particularly in Mustapha mall), I would advise the credit card withdrawal. That's now my standard upon reaching the airport of destination, I look for an ATM machine.