Hello davideugene,
Unless you have some serious cash, I would not recommend buying a camera at this time. Instead, spend the money producing an ultra-low budget film, or completing the development of a low budget project. Most successful filmmakers, including most small production companies, do not own their own cameras – they rent. There is no need for it and there are other more critical places where you need to invest the money – even a post-production/editing module would be more appropriate right now since it would save you even more money in the long run.
Regarding what most people use, most indi filmmakers use 16mm. They do that because if they hit the jackpot and the movie is successful, the distributor will pay to get it blown up to 35mm. So, having a 16mm will not necessarily keep you from getting distributed. However, having a 16mm in the first place means you are filming a ultra-low or no-budget film, which by default means that you will not get distributed. That is a harsh but true statement – as accurate as saying that you will not win the lottery if you buy a ticket this weekend. More people win the lottery every year than ultra-low budget films find distribution deals.
We use 16mm for documentaries, TV, and corporate video, and 35mm for features. We own a 16mm and rent the 35mm packages. The only reason we own the 16mms is because it makes financial sense for us based on the volume of production services we offer, not because we want or need to own a camera to film our movies.
In sum, rent your camera and use the money for something else. Later, with more working capital, and with the infrastructure in place to truly benefit from owning your own camera, you could invest.
Best wishes.