Probably like 100$ BTC...
i cannot agree with you, such amount of money will not allow you to trade as much as you want, to be honest you might need way more money tahn that in order to make some money
i htink that you would need something like one thousand dollars in order to be able to move the price a little bit and try making some money though i have never tried doing that
why not there is leverage nowadays, you don't need to invest much, this is the point of leverage, you can do good even with 0.01, and 500x leverage
the bad part is that for bitcoin i'm not able to find an exchange with that high value for leverage