I’ve got a cache of estate sale finds and frequently tune into Antiques Roadshow to shout out guesstimates as if I were watching The Price Is Right. Some of Roadshow’s most reliable experts work at Bonhams & Butterfields, and on the last Wednesday of the month that venerable Hollywood auction house offers a no-fee appraisal for as many as five items. A porcelain pig flask that was recently brought in sold at auction for close to $10,000. A Tiffany-made bicycle rolled away for $57,000. Who knows? That little Hot Wheels Beach Bomb of yours might be worth more than a new Mercedes.