Forex: What is the minimum amount needed to trade?

It differs within brokers. Every broker has their minimum deposits. Some brokers allow as low as $1, while other will take $50 or $100 as their minimum limit. If you are an experienced trader, you should invest as much as possible because the higher your deposit, the more money you get for each successful trade.

With most brokers providing accounts with as little as $500 in initial money and some going as low as $100, getting started with Forex on almost any budget is simple.

Is it truly possible to trade effectively on the minimum?

As you'll see, it's not as simple as a yes-or-no response. The bare amount you'll require will be determined in part by your trading style, your broker, and whether you want to use any earnings as a side business (or main source of income).