Your city (or County) whatever the case may be, would most likely consider that you are doing business in there territory. Therefore, yes you would need to get a biz license, even if you are conducting business in your own house, and yes you will need to collect a sales tax from your buyers. Nobody gets out of this part of the deal. Not legally anyway.
A small business license is based on the city, state and county where you operate your business and each of these will have different requirements for licenses depending on the type of business. One of the best places to go to find out about a small business license and other home business requirements is www.business.gov. Not every small business needs a Sales Tax License or Permit. Your State Franchise Tax Board will provide you with the details or go to www.irs.gov
I don t know if you need a business license to do business on line. But if you do, it is very easy to get a business license. Just go down to City Hall and check with the city clerks office. The fee is usually around $100. Not too expensive. They will tell you what the requirements are. It usually means running a fictitious business name ad in your local newspaper. Your newspaper can tell you what you need for that. It usually costs about $25. It s all easy stuff. No big deal.
