My absolute favorites are games I consider masterpieces, however objectively there are two games in my opinion that are as close as it gets to perfect: The Legend of Zelda: Ocarina of Time, and Chrono Trigger.
Not counting World of Warcraft's monthly subscription/expansions/account services for 10 years on and off. As well as League of Legends Champions/Rune Pages/Skins, simply because I have no idea how much I actually spent on those games (but it was definitely a lot).
Collector's Edition ($90)
Digital Pre-Order ($60)
Persona 3 DLC ($7)
I've bought Resident Evil 4 and Ocarina of Time 5x each as well, so just about over $100 each for those.