You'll need to look at what you can afford in start up costs, you'll need all the same things a private contractor would need as you do a business, but having your own business might appear more professional and appealing to your clients in the long run. You'll need t obtain your own software, business registrations, insurance (liability and business insurance), compliance setup/procedures, etc. I THINK the diff between being a contractor and your own business come down to accounting/taxes really but you should talk to an accountant for those issues. You'll also need to have your own contracts for each client.