Sales tax is not included within the product costs that are visible during the product creation process or on https://www.spod.com/products. As tax varies by state, city or even district the sales tax is always added on top of the product costs after an order is made.
Sales tax can only be calculated after the order has been placed with SPOD and therefore it’s only visible on the invoice. You can find this information on the order detail page.
For some states, the merchant can provide SPOD with a Resale Certificate that will enable SPOD to drop the sales tax charge..