There's a spectrum among F2P games as well. There are games that are designed to coax the player into constantly spending increasing amounts of money by either inconveniencing them (wait times, slow or nonexistent progress) or by providing them with massive advantages against other players. Towards the softer side, there are titles that are solely selling cosmetic items - but they can be so incessant with it that people, especially kids, feel pressured into purchasing them, sometimes even out of peer pressure (see: Fortnite). Finally, the mildest kind are games that have a free mode that is little more than a demo, but you can make one-time purchases to permanently unlock more content, which isn't too dissimilar to expansion packs of the olden days. Prime example for this: The Battle of Polytopia, a Civilization-lite. On mobile, you can permanently unlock more tribes and thus larger maps and multiplayer with very small one-time purchases.