The strongest case for a small first deposit has nothing to do with markets. You're testing a process — signup, verification, funding, a first position and, most importantly, a withdrawal — and that test should cost as little as possible.
Run the full loop at the minimum. Deposit, wait, withdraw part of it, and watch how long the money takes to return and whether it comes back to the method you used. A platform that handles a small withdrawal cleanly is one worth scaling into.
Only after that round trip does it make sense to think about size, and even then in steps rather than one jump. A bigger deposit doesn't make a strategy work better — it only makes the same outcome larger in both directions.
Why the first deposit matters most
The first deposit sets the habit. An amount chosen because it's comfortable tends to lead to calm decisions later; an amount chosen because it felt like the ceiling tends to lead to decisions made under pressure.
A sensible starting point
Money you wouldn't need back within a year, in an amount whose loss would sting rather than damage you. That's a personal figure and nobody else can set it for you.
Adding to it later
Topping up a balance you already understand beats starting large and learning the hard way afterwards.
Questions worth asking before you send anything
How do I withdraw, and to where? What gets deducted, and by whom? Who do I contact if something looks off? A platform that answers all three clearly, in writing, is behaving the way it should.
Investing carries risk, including the possible loss of some or all of the capital you invest. The value of investments can go down as well as up, and you may get back less than you originally put in. Never invest money you cannot afford to lose.