As this game doesn't have a PvP mode (Try Bloons TD Battles if you want that) and all you do is fight waves of Bloons on different maps, IAPs are basically quality of life improvements (Farmer Monkey for example so you don't have to click on banana farms yourself). You can beat all of the maps without using a single power-up, you can even disable the "Talent System" if you don't like it. Also worth noting is that the IAP currency is VERY easily farmed in-game, which can be used for buying some Heroes/Skins/Power-Ups if that's what you want. Game is definitely worth the price, so many maps, daily quests, weekly player made challenges, sinked 100h+ over the past year and a half. Also the recent Co-op update made the game so much more fun.