Let’s take the original pure shopping round, the grand prize is a luxury car and money costing compiled front game winnings of, say, $600. What if each day they let you buy a smaller prize...yet come back? The drawback to buying is you’re further away from the end goal.
There isn’t “the lot” on display, just the new temptation each day. As a champion keeps returning, the prizes get bigger, though prices stay around $100-200. The host could haggle as in the front game. As the car approaches, maybe the temptation does require exiting the show but for thousands of dollars or a smaller car. Then again, a champ could just buy the small prize each day and play as long as he can.
I’m trying to leave shopping as the final act, but make the champion’s decision more interesting. Instead of stay or never come back, it’s spend or save.