Espresso machine. I was spending 8 bucks a day on lattes, and now I make them myself and stopped going to the cafe every morning, saving time and money. I also think it's a fun morning ritual to grind the beans, measure everything, tamp, distribute, steam the milk, etc.
Btw I also impulsively bought a Steam Deck and use it way more than I thought, it's amazing and you'll love it!