Each broker has its own set of minimum deposit requirements, which can range between $1 and $10,000. Brokers like InstaForex and ThinkMarkets accepts deposit as low as $1. But other brokers like LiteFinance and FIBOGroup require minimum deposits in the range of $50.
It is best to adjust the minimum amount you can invest in forex with what you can afford. Therefore, you won't be under the pressure of trading with too much money in the market.