I'm getting some rather serious consulting work on the side of my main job. Serious in that I'm filling out NDAs and service agreements for the small-ish company I'm being contracted by. The guy I'm getting the work from wanted to know if I had a business to associate the work/payments/contract with, and when I said no he somewhat recommended it - but with no real reason.
So, should I start a business for my consultancy work? What are the advantages/disadvantages of that? Corporation, LLC, what? How much paperwork, time, and money is it to start a business? (I'm in the USA)