P2E games come in various forms, and the approach applies to both skill-based and chance-based games. While you can play some games for free at first, others demand a purchase, which impacts whether or not they are legal. Whether or not they need participants to buy in, games of skill are unlikely to fall under the purview of gaming authorities. However, it depends on various elements regarding games of chance. If there isn't buy-in, it depends on local laws and how authorities interpret them.