The first step.

Ok, so the first thing you need to do, is to take into account, you are starting a business. This is real now. No turning back, no half-assed effort. REGISTER your business with your state goverment. Typically it would be at www.yourstate.gov. It's usually under 100 USD, cheap huh? You'll have many options, typically sole proprietorship, partnership, LLC, or S or C corp. Each one of them helps you in a different way, you can find out about the differences on your state website. Another helpful source is the IRS. Here's a page all bout starting your business.

Once you register your company you are eligable for your TaxID. If you want to do retailing on the internet (i.e. selling someone else's things for them for a fee), you usually need your Tax ID. This may cost around 30-40 USD and is for collecting sales tax in your state (if applicable). Usually when selling online, you may not need to collect sales tax except for items sold in your state. Try googling the phrase "incorporating in (your state)" to get some options. Here's some information I pulled up for Florida. There are many legal-type-guys who will take care of all the fees and paperwork involved for a flat rate. This might be something to look into. Remember always delegate! One of the best parts of working for yourself, is that you tell others what to do, for money. Not the other way around!