Just found this by accident.
I was doing a architect job and I had a sketch in my family inventory that I had done on the drawing board and thought I would added to the job for some extra decoration. Later I decided not to include it so I grab it off the wall and put it back in my family inventory and heard the ka-ching and saw $540 floating up the screen like it had sold the sketch.
I look in my inventory and it was still there but then I noticed the remaining budget for the job looked bigger than I thought it was.
I thought I would try it again to make sure I was seeing right. I picked up some VR Goggles I had got as a celebrity then dropped them back in the family inventory. Same thing, ka-ching and $5,700 added to the remaining budget but I still had the goggles.
I finished the job with that money and really deck it out and they loved it.
Might be interesting to mess with. Go to do a bathroom make over and add that $15,000 car in my inventory to the budget a few times and build them a whole house and see what they think.