The best option is to buy at a pre-sale before listing on the exchange, then there will be at least some chance of profit. And buying already on the stock exchange in the hope of getting a profit is the most unstable option, since those who bought earlier at a big discount will sell first.
taking part in presale is most profitable but who knows which coin will pump like pepe. every day new coins Presale is going and we cannot waste our most if fund in these meme coins. 99% of these presale are results in loss and only 1% comes out to be a coins like pepe. Moreover if any one given allocation in presale they will not be given all coins at once. Their token will be locked and will be unlocked according to Unlocking period and we know these coins are not for long term. Investing in these coins is same like jackpot.