If you sell your game, or if your game has direct donations inside of it that you make money from (so the donations that are not charity), or just generally directly promotes something that you make money from, then you need to pay $2. If a game has a link to a patreon, or something like that, I wouldn't consider it as a direct promotion. If the link is just there (e.g. in the beginning of a game and at the end) and not promoted 'aggressively' (e.g. it's not over the whole screen for some time and doesn't take most of the player's attention, and doesn't have something like "If you want more games from me, subscribe to my patreon"), it's allowed.
If you have any more questions, or something is unclear, feel free to ask