If you received a 1099K you will enter the numbers that are reported on the form. If EBay collected the sales tax, you can deduct that as a miscellaneous expense. You can enter Miscellaneous Expenses by visiting business expenses, then near the end it will give you the option to enter other expenses and type in the description of the expense along with the amount.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"