Sales taxes are one of the most complicated taxes if you ship or deliver things and have to charge based on the DESTINATION.   It's easy if it's based on the shipping location.   The complexity comes in the fact that multiple sized taxing districts can all have different tax rates and a location can fall in or outside of multiple districts.    Let's take an address in say Denver it would be subject to state sales tax, city and county of Denver sales tax, the cultural facilities district tax, the RTD tax, the staduim district tax and possibly a special district tax or two in various smaller areas.    If you went down the road a bit you would drop all but the state tax and RTD tax but pick up say Douglas county sales tax and a city sales tax and a library district tax.   And of course each tax has different items subjected to the tax food exemp from 1 but not others etc.