They live in a nice neighborhood in Ponyville. Twilight obviously has some money. But she seems to downplay it all the time by being frugal. I'm imagining seeing the Princess of Friendship just chilling in her yard with Spike in a blow up pool with water-wings and sunglasses. It's such a silly image.
^ True. I remember one of the best views was this episode with some fire trucks.
I'm just loving seeing Fluttershy so happy there though.