Thanks for the replies.  I am actually already set up as a sole prop, but haven't made the decision to whether I wanted to do this.  I sell a little on amazon and ebay already.   I definitely wouldn't charge sales tax on top of a price on craigslist, but I wasn't sure if other dealers wrote receipts out for their customers if I could simply collect the money and then pay the sales taxes out of my cut.  My worry about representing myself as a dealer, is then less people would want to buy from me (vs. an owner) and possibly having to accept returns, etc. I was curious to see what other people's experience was.