Is there Zakaat on a car bought to be sold?

Yes, there is Zakaat on any movable or immovable properties that bought to be sold. The value of zakaat depends on the related market value of the car on the day that the zakaat is due. That is on 1st Ramadhaan or the date of Ramadhaan you fixed to give Zakaat yearly, value the goods or land that day. The value of your car is the selling price you would get on the market in exchanged of your car. This is not the book value, nor the buying price and not also valuation value. But the price you would get in selling the car. We are aware that once a new car is bought and used even for a few days, the value drop by at least 20 %. Hence the Zakaat would be calculated on the reselling value of the car. We are aware that this drops when there is demand for the car. This is called ‘’Qimah’’ in Arabic.
Know that Qimah is not the book value nor cost of buying and cost incurred. But the reselling value. In this case, we won`t take into consideration the road taxes paid, nor the insurance since all these are not accounted for when people are buying the product.
In the very same way, when calculating the Zakaat of jewelleries, we have to look at the reselling market value of the jewellery. Except for antiques, no one on the market would pay more than the gold weight of the jewellery. Hence the zakaat of jewellery is accounted for same way as stocks: on the related market value that people would be ready to buy the jewellery. Allama Shami also generalise the same principle of Qimah for stocks, jewelleries that are used or not used:
Durul Muhtaar

(والمعتبر وزنها أداء وجوبا) ولا قيمتهما (واللازم) مبتدأ (في مضروب كل) منهما (ومعموله ولو تبرا أو حليا مطلقا) مباح الاستعمال أو لا ولو للتجمل والنفقة، لانهما خلقا أثمانا فيزكيهما كيف كانا (أو) في (عرض تجارة قيمته نصاب) الجملة صفة، عرض، وهو هنا ما ليس بنقد