What transaction costs will I pay?

Although dealers who are regulated by NFA must disclose their
charges to retail customers, there are no rules about how a dealer
charges a customer for the services the dealer provides or that limit
how much the dealer can charge. Before opening an account, you
should check with several dealers and compare their charges as well
as their services. If you were solicited by or place your trades
through someone other than the dealer, or if your account is man-
aged by someone, you may be charged a separate amount for the
third party’s services.
Some firms charge a per trade commission, while other firms
charge a mark-up by widening the spread between the bid and ask
prices they give their customers. In the earlier example, assume that
the dealer can get a EUR/USD spread of 1.2173/75 from a bank.
If the dealer widens the spread to 1.2170/78 for its customers, the
dealer has marked up the spread by .0003 on each side.
Some firms may charge both a commission and a mark-up. Firms
may also charge a different mark-up for buying the base currency
than for selling it. You should read your agreement with the dealer
carefully and be sure you understand how the firm will charge you
for your trades.