500 dollars is more than just enough. Of course, you can invest everything at once, but I would advise you to start with $ 100. And when you open up - then you will need the rest to buy conscious, planned and predicted. Well, maybe even for the purchase of additional software.
At least 500 dollars is not such a large amount for an investor, But if a person is a new trader, then of course you can practice with a smaller amount.