Maple VaulthornThe strongest argument 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 you want that test to cost as little as possible.
Run the full loop at the minimum deposit of C$350. Deposit, wait, withdraw a portion 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 a single move. A bigger deposit doesn't make a strategy work better; it only makes the same outcome larger in both directions.
Why the first deposit is the one to think about
Your first deposit sets the habit. An amount chosen because it's comfortable tends to lead to calm decisions; an amount chosen because it felt like the maximum possible tends to lead to decisions made under pressure.
A workable starting point
Money you wouldn't need back within a year, in an amount whose loss would be annoying rather than damaging. That's a personal number, and nobody else can set it for you.
Adding to it later
Topping up a balance you already understand is a far stronger position than starting large and learning the hard way afterward.
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 wrong? A service that answers all three clearly, in writing, is behaving the way it should.
Investing involves risk, including the possible loss of some or all of the capital you invest. The value of investments can fall as well as rise, and you may get back less than you originally put in. Never invest money you cannot afford to lose.