I want to start a website for a niche group of "widget" collectors. The site will contain facts and references and other tidbits for these "widget" collectors. It will also be a very easily searchable database of "widgets". The individual "widgets" will have its own fact page and (hopefully) links to ebay, amazon, and other sites to purchase the "widget" from which I will receive affiliate commission.

Other info, I have the website name reserved and a host. Have consulted on site layout and management. Just need to pull trigger to have it built. Site is a bit too much to do myself or through cheap website building program. Over 8,000 different type "widgets" to eventually list but will start with a niche inside niche of about 200 items.

So here is my question(s):
Since I will be registered as an affiliate, what do other items do I need to obtain?
Do I need to set up a business identity or can I just run under my name?
Should I do a DBA?
Since I am online, who do I need to register with?

I have run a business so bookkeeping, marketing, etc are not a problem. Just need help to make sure ducks are in a row for this type business at startup. Since I am on a budget, I want to test the water and see if I can build some income without unnecessary expenditures. If it turns out to make some real money, at that point I can reevaluate my structure and incorporate if needed.

Thanks,
Curtis