It’s a problem I am familiar with because an author I know, who sells her books through a number of different online purveyors including Smashwords, Kobo, and DriveThruFiction (as well as Amazon and Google Play), has had to wrestle with it: when a business located in one state sells something to a customer located in another state, does the business have to collect sales tax from the customer and remit that tax to the customer’s state?
The answer currently is, no, but apparently there is a case pending at the U. S. Supreme Court that could change that answer. There’s a good explanation posted at the Volokh Conspiracy site.
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