If the instructor was from out of state, you basically purchased from her as if she was located in her state. She possibly charged you her state sales tax. She had to show that sale from her location.
On the shipping charges for the book, the shop may have had to order those as a special order from someone that did not deal through their standard distributors thus they could not combine order amounts to place a minimun order to get free shipping. Occasionally I have to do this, but not often.
OzarksGma