Once you've decided to develop a car marketplace app, it's better to get a professional consultation because as we have mentioned there are quite a lot of different types of car marketplaces that provide different services. After a profound consultation, you may have a better understanding of your field.
Overall, it's quite a complex process that requires much effort and research. Therefore, even if you have some experience, it's still better to start by sharing your ideas with a specialist. This person will provide you with some knowledge and you will have a deeper understanding of how to sell new cars and old ones.