What it means to the super rich:
The price of an item sold at auction when the auctioneer slams the gavel and yells, "sold!" Super-rich bidders know that the auction house charges a hefty fee, usually a percentage of the hammer price, which could add hundreds of thousands of dollars on top of the price.
Super rich guy: Dude, that Ferrari was a steal for $1.3 million.
Super rich car collector: Bro, that's just the hammer price. I wrote the check for almost $1.7 million