There is no limit on trading you can start trading any time with very tiny amount of money. You just need skill and strategy to earn from trading however more amount of money will get yoi bigger profits.
there's indeed no limit for trading or any requirement but if the amount were too tiny then the trading will become useless,the money will be cutoff by the fee and endup not gaining profit but lose even you just make money out of selling altcoin with higher price,such a waste of time to be honest