The main difference in WordPress.com versus WordPress.org hence .com meaning commercial and .org for the organization. If you are looking to make money, start with WordPress.org. If you want someone to make money off of you, start with WordPress,com.
There is a small investment in starting a website using WordPress.org (or software) tools and information. Registering a domain and hosting are the small investments but provides more access to website functionality. WordPress.com offers a free but limited website platform. Here are aspects of comparison to think about.