The U.S. Supreme Court has overruled decades of “judicial law” which previously held a selling company did not have to collect sales taxes for a State in which the selling company sold goods but did not have a physical presence in such State.  That has now changed! and the playing field is going to change now for online retail sales particularly.  The SCOTUS June 21, 2018 opinion is SOUTH DAKOTA v. WAYFAIR, INC.