If it's a permanent fixture, it's part of the budget. Otherwise, it's staging and they have to buy it or out it goes.
You'll notice that when they build things for the kids, Jo will mention "this is a gift" for the girls/boys/kids...that means she and Cliff are actually giving it to the family at no cost to them.
I always wondered why they never or rarely used the furniture the couple actually owns. Is it that bad? That old? Don't have any? To me, I don't want to see a stage, I want to see MY STUFF in the house, you know?