Starting an Ebay business?

I am a stay-at-home mom/wife and I recently graduated from college. My husband and I recently came to the conclusion that we want to have another child, so the smart thing to do, we decided would be to start up a business, and I want to start with an ebay business then go from there. Well, I need to know how to go about it all? I want to get a business license, so how do I take the first steps in getting that, and when I get a business license does that entail an LLC or is that different? Also, how much does it cost to get a business license/LLC? Thanks.