Personally, I believe the best moment to purchase any cryptocurrency is when the price of the token you want to purchase is low, so you can sell when the price is high. Another occasion is when a project is just getting started, such as when I invested in Paragen $Rgen, a just announced Binance smart chain initiative. It was listed on pancakeswap and CMC, which was part of my investigation. It's a long-term multichain metaverse incubator.
So those, in my opinion, are the best times to buy.