Answer: amount you can afford to lose entirely without affecting your life. Not "dream amount". $500-2000 to start.
The answer is not as much as possible. It is the amount you can lose completely without affecting your life. For most beginners, USD 500 to 2,000 is enough to learn real execution, spreads, slippage, withdrawal and emotional control.
With USD 50, proper position sizing is hard. Normal volatility can push the account close to liquidation. Very small accounts often push traders toward high leverage and lottery-style behavior.
If you start with money you cannot emotionally afford to lose, every move becomes pressure. You will close early, move stops, revenge trade and learn fear instead of skill.
Use demo first to learn the platform, then a small live account to test execution and withdrawal. After three months of planned trading, scale gradually. Starting capital is not for getting rich; it is for buying real market experience.