Do you understand that there is a big risk in buying coins without a real market price?
Usually, the owner of the coin wants his product to be valuable and most often overestimates it. In 99% of cases, just after listing coin to any exchange, its value falls up to 90%.
As I know, it is possible to buy them directly from the team ^{in most cases} through their media channels (Telegram, Discord etc...). you have to be very careful here, you can easily be deceived by fake team members.

certainly, I say again, the probability that you will be deceived or that you will overpay some coin is 99%.
play roulette, the greater the chances of winning.