Hi, this is the classic chicken and egg question, but there are several considerations that will partly depend on your project. Normally it makes sense to focus on supply before demand, in the early days, but it's always a question of keeping a balance. And reacting to the needs of your users. If they are looking for 4x4s, get more of those. If they are looking for sports cars, get more of those. In all cases, remember that your suppliers deserve transparency and require honesty, there is no point in pretending you're bigger than you are. Good suppler relations are built one by one, they've got plenty of alternatives, you'll just have to do the leg work.

I designed and built several used car marketplaces, through my software company, learned some tips and tricks that I'd be happy to share on a call.