Each time you sold an item to a buyer located in a different state, you’d need to determine the applicable sales tax, collect, and then remit the tax to the buyer’s local taxing jurisdiction. To do so, you will be required to hold a sales tax license in each state in which buyers purchase items from you, and in most cases a corresponding business license. By doing so, you will be subject to that jurisdiction's regulations and police powers.
More importantly, this case has many eyes on it. In fact, 25 other states have similar pending legislation. And, 35 states filed a brief in this case in support of South Dakota.