There's nothing exact amount recommended in trading if you investing huge amount you can get huge amount of earnings but don't forget the high risk of loses small investment small loses if ever.
I remember that when I started trading, I used to trade with very small amounts and once getting profit I increase my investments. It was just planning so that even if I lose in few trades, my overall money was not lost.
It doesn't matter at where you start, it is important to use yourself better instead of your money. If you really work yourself instead of your money there are ton of money to be made on bitcoin and crypto world.
If you want to trade instead of trading your money for more money you can start as little as zero and start trading your time for money which we usually call work but in crypto world it could be as little as sharing stuff on twitter. So the starting amount could be as low as zero yet you can make more money than people who lost thousands of bitcoin during the bear market times.