It's important to consider whether a Forex broker and their trading platform will suit your trading style. For example, you might be interested in following a Forex scalping strategy, which involves making a high volume of small profits on small currency movements. In this case, you would need to ensure that any potential broker has minimum distance between the market price and your stop-loss and take-profit.
Due to Forex CFDs being leveraged, traders can access large portions of the currency market at a very low margin - sometimes as low as 1/500th of the size of the market they want to access (based on a leverage rate of 1:500). There are few additional costs as well - most Forex trading accounts have little (or no) commissions, order fees, and account management fees. If there are any trading fees, these are usually a markup the broker has added to the spread.
The spread, in Forex, is the difference between the bid and ask price of a currency pair. For example, if the Bid price of the EUR/USD is 1.16668, and the sell price is 1.16669, the spread will be 0.0001, or 1 pip. In any Forex trade, the value of a currency pair will need to cross the spread before it becomes profitable. To continue with the previous example, if a trader entered a long EUR/USD trade at 1.16668, the trade wouldn't become profitable until the value of the pair was higher than 1.16669.
In return for executing your buy and sell orders, forex brokers will either take a commission per trade or a spread. A spread is the difference between the bid price and ask price for the trade. The asking price is the lowest price that a currency pair will be offered for sale and the bidding price is always lower. When forex brokers successfully execute a buy with the lower bid, they will take that difference — the spread — as payment.