What is the buyer's premium?
The buyer's premium is a charge in addition to the winning price of an auction item, or lot. The winning bidder is required to pay both the winning bid price and the percentage of that price called for by the buyer's premium. Unless otherwise stated directly in the auction, the buyer's premium will be 13%.
For example, if the winning bid is $25, then the buyer's premium would be $3.25 (13% * $25). The total amount due by the winning bidder is $28.25, plus any applicable sales tax.