Note: Brokers can legally say no slippage when advertising, because they are a market maker, and there not technically slipping at the rates they are providing, however ask them to fax a guarantee that there will not be any slippage regarding quotes given from interbank opposed to quotes given from the broker in question. Better yet, just open an account with any broker you wish, and compare the quotes given by them and quotes given from commerce demo platform, or Intellicharts.
