Like UM said:
Friday night is a live auction.
You bid live, against other bidders!
Just make sure to arrive by 7:30pm to ensure you get a bid panel number, as the auction starts at 8pm.
At the end of the auction, whatever doesn't get auctioned off, you can grab and take to the auctioneer and offer a "buy it now" price.
Then there is the silent auction on saturday, where you put your highest bid on a sheet, and keep coming back to see if anybody outbid you.
It is absolutely amazing, too much fun, and completely free, whether or not you have a sat or sunday pass.
And in the past we've had surprise guest appearances by voice actors!
Hope to see you there!