Look in the OP. The chance that it is a worthless pump-->dump-->abandoned-by-dev coin increases with each of the following words/phrases being present: revolutionary, investment opportunity, premine for development/promotion, the next bitcoin, the next dogecoin.
You're right, coins have no intrinsic value and they are priced at whatever someone is willing to pay. People saying a coin is "cheap atm" or "overpriced atm" are attempting to lure you into helping them make a profit. It's hard to judge to value of a coin, but I think that
CoinGecko does a good job of weighing in the important factors.