If anything you select in Payments and Product Sales has an incorrect tax amount associated with it, follow the steps below to troubleshoot this issue:

1. From the More Options Menu, click on Business Defaults.
2. Select the Taxes tab.
3. Here, under Change Tax On, you will find a list of Tax Category's and their associated Rate. Make sure you have at least one Category with a Rate of 0% (This will most likely be the No Tax - Default Category) and one Category with the Rate equal to your local sales tax.
4. If you need to make any changes here, click Edit in the upper-right corner and then click on the Category you wish to change.
5. A Edit Tax Category pop-up window will appear. Change the information here as needed and click OK.
6. When done here, Save any changes made and return to the More Options Menu.
7. Now, click on Inventory Mgmt.
8. Select the product in question.
9. Click Edit in the upper-right corner.
10. Click on the pull down menu for the Tax Category and select the appropriate one.
11. The Tax Rate should change when a different Tax Category is selected.
12. Make any other necessary changes and click Save in the upper-right.

Your product should now calculate the correct tax amount when entered into Payments and Product Sales.