I think to earn at least a little, you need to invest at least $ 100. Smaller amounts are simply ineffective for investment.
You will earn the same percentage whether you use a small amount of money or a big one the difference is the absolute size of your earnings, obviously with a bigger capital your net profits will be way higher than if you have a small capital.
$100 is also still ineffective for the calculation and speculation of more profits, but at least much better than $10.
I suggest to use large investments/deposits in order to have a clear calculation to measure the threshold of defeat and victory.