If you plan on exchanging money, banks offer the best exchange rates and a smaller commission, but the GWK is the most convenient if you're heading out from the train station. The exchange rate is reasonable but the commission is 0.75% with a minimum charge of €3.25 and a maximum of €7.50. It's located outside the station, down the escalators and to the left. There are also two ATMs outside the GWK from ABN and ING. Also sending money through Western Union is possible here, as buying telephonecards.