If you want to charge your buyers or sellers FEES such as Sales Tax or Buyers Premium:
From the Configurations: Global Fees page, click the green ADD button in the upper right corner.
Select the Category option:
Tax
Sales Tax, applied to a bidders invoice. It can be a flat rate or a Percentage Rate (most common). Simply enter the amount, without the % symbol.
Fee
Optional item level fee, charged to the winner of the item
There is an optional, 'tax applicable' checkbox that allows you to make this fee taxable.
Premium
Buyers premium, applied to the winner of the item. Can be taxable, can be a Sliding Scale.
Commission
Applied to the settlement report for the Consignor. Can be a Sliding Scale.
Seller Fee
Optional, applied to items for the settlement report.
Other