A coin that has a Market Value of $10,000 will typically receive an auction hammer of $8,550. This is because the buyer has to pay an additional 17.5% Buyers Fee of $1,450. So he pays $10k. Then the Seller (you) receives a paltry $8,124. ($8,550 less the 5% Sellers Fee. The auction house receives $1,877 or a 19% commission.
The only winner here is the auction house!