Keep me logged in until I sign out. The simplest form of business entity is the sole proprietorship. If you choose this legal structure, then legally speaking you and the business are the same. You can continue operating as a sole proprietor as long as you're the only owner of the business. Establishing a sole proprietorship is cheap and relatively uncomplicated.
States differ on the amount of licensing required.
In California, for example, almost all businesses need a business license, which is available to anyone for a small fee. In other states, business licenses are the exception rather than the rule. But most states do require a sales tax license or permit for all retail businesses. Dealing with these routine licensing requirements generally involves little time or expense. However, many specialized businesses such as an asbestos removal service or a restaurant that serves liquor require additional licenses which may be harder to qualify for.