Small minimum deposits can range from $1 to $10. Here are three well-known brokers that represent those small minimum deposits:
InstaForex allows a minimum deposit of $1 in all of its trading accounts. Dedicated to beginners and small-cap traders, InstaForex is also supported with leverage up to 1:1000 and the freedom to choose trading with zero spread or no commission.
Traders can enjoy trading in RoboForex with a minimum deposit as small as $10. Interestingly, the condition is applied to more than one account type, so traders can have more options when choosing the right trading condition. The $10 minimum deposit is available in Prime, ECN, ProCent, and Pro accounts. Prime and ECN accounts support spreads from 0 pips while ProCent and Pro accounts are available with spreads starting from 1.3 pips.
Forex4you only does not require a minimum deposit, as traders can trade with $0 in all account types. It supports maximum leverage of 1:1000 and spreads as low as 0.1 pips. Also, there's no commission charged for traders who apply for Cent and Classic accounts.
Apart from those three, there are other forex brokers with low minimum deposits that you can consider. The list can be found on this site.