If I want my sims to have less money but not a crazy amount of usable items, I decorate. I love having decorations and clutter around the house. I also like to do a lot of outside decorating and landscaping such as trees and flowers. This can take up a lot of money, but not give your sims a ridiculous amount of items they don't need.
Also, if you want to up the difficulty and get rid of some money, you can buy expensive items like statues and keep them in the household inventory. That will both take away money and cause your bills to go up, but won't take up space.