How to sell you cars online through social media

When you talk about selling or buying stuff online then you need to understand and realize the fact that people all over the world are using online platforms to buy and sell things. People actually feel more comfortable trading online rather than going out physically and buying or selling something. When talking about cars I even prefer to buy used cars in Tokyo, Japan online through different platforms and when you talk about selling them I usually use my social media account to get the word out to sell them. Why pay to advertise when you can use social media for free?