What are good ways to keep the player spending in a single-player RPG?

I’m designing a game where I want the player to take the in-game money into consideration as opposed to majority where they just get rich pretty much all the time with nothing meaningful to spend it on. What are some good ways to keep them spending their money without making it feel like a tedious chore?

I’m already planning to have monsters nor quests not give gold.

And if preventing them from becoming extremely rich eventually is not possible, at least mitigate "easy" ways of generating infinite income. I want them to struggle with their money.