Transcript for Tag Sale Bowl Sells for Millions at Auction
all had this fantasy. You buy a little something at a yard sale for nothing and it ends up making you very, very rich. Abc's nick watt now on the $2 million gift from nowhere. Reporter: Bought at a yard sale for three bucks, this bowl sat on a dusty mantel for five years. After a bidding frenzy at sotheby's, it just sold for over $2 million. How did the anonymous seller react? I got an email that said it -- capital letters -- wow, and then wow again with a line of exclamation marks so I can say that they were very pleased. Reporter: It's a 1000-year-old chinese bowl. Totally inspired, this morning i went shopping, looking for anything vaguely chinese. If there's a fortune in this box, I will quit my job right now. It has got some age. It's a pattern I haven't seen before. Reporter: Exciting! We asked our experts for top tips to find a fortune at a flea market. If something is old there will be much bigger chance it's worth money. Reporter: This old copy of the declaration of independence cost $2.48 plus tax at a thrift store. Turned out to be uber old and sold at auction for nearly half a million. And look for something chinese? Chinese is one of the hardest fields to appraise. Reporter: Even experts don't always know the chinese gems from the junk. Upping the odds of a masterpiece with a $3 price tag. Always buy what appeals to you and you will never go wrong. Reporter: Back to my little cup. Certainly before 1872. Reporter: Really? It's old, it's chinese, and i like it, but -- the reality, you'll probably get no more than five to $10 for it. Reporter: Proving luck really is the key. So I'm not quitting my job. See you tomorrow. Nick watt, abc news, los angeles.
This transcript has been automatically generated and may not be 100% accurate.