How much money do I need to trade forex?

Forex dealers can set their own minimum account sizes, so you will
have to ask the dealer how much money you must put up to begin
trading. Most dealers will also require you to have a certain amount
of money in your account for each transaction. This security
deposit, sometimes called margin, is a percentage of the transaction
value and may be different for different currencies. A security
deposit acts as a performance bond and is not a down payment or
partial payment for the transaction.

Dealers who are regulated by NFA are required to calculate and
collect security deposits that equal or exceed the percentage set by
NFA rules. Although the percentage of the security deposit remains
constant, the dollar amount of the security deposit will change
with changes in the value of the currency being traded.
Some dealers guarantee that you will not lose more than you
invest, which includes both the initial deposit and any subse-
quent deposits to keep the position open. Other dealers may
charge you for losses that are greater than that amount. You
should check your agreement with the dealer to see if the agreement
limits your loses.