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This is Mastro’s only live auction all year, and like the company’s three annual “premier” auctions, where the average lot goes for about $5,000, this one’s for high rollers. The minimum bid on the cheapest lot is $2,500, and 19 lots start at $20,000 or more. Don’t expect to see a copy of that 1989 Upper Deck Ken Griffey Jr. rookie card you’ve been holding onto. But if you wish you’d caught the Kid’s 600th home run ball, now’s your chance to chase it–the starting bid is just $24,000. (Low rollers might consider one of Mastro’s three annual “classic” auctions, where the average lot goes for about $1,500. The next one is in October.)

The live auction is intended for serious bidders only, in part since the capacity in the second-floor room where it’s being held is just 300. But if you want to attend, you can register with Mastro and be prepared to make a $100 donation at the door; proceeds will benefit Derrek Lee’s 1st Touch Foundation. (The Cubs’ first baseman won’t be attending the event, but he has donated several game-used and autographed items, sales of which will also benefit 1st Touch.)

Buck Weaver game-used bat, 1911-’15, the “only known example” from his professional career

And here are some other highlights of the auction: 

Signed contracts for the 1976 Muhammad Ali vs. Ken Norton boxing match