Putting aside most of the issues with the show...why did Rossi call the Bonus Round "the shopping spree of a lifetime" if contestants couldn't buy more than one prize? Several players who had more than enough to buy more than one prize couldn't, and it's not like the "Temptation Dollars" were legit US currency anyway.
No Budget, basically. Yes, "only one prize" was also the case on many other versions of Sale (barring the 1983 Tournament of Champions in America), but in many cases there were prize levels past the car - like, say, the Lot. A few versions did have a car as the final prize, but none of those had an appearance limit either.