Once a year, one lucky (and wealthy) person gets to have a one-on-one lunch with billionaire Warren Buffett . The winning bids have gone as high as $3.5 million, all to benefit the San Francisco-based charity called the Glide Foundation.Bidding, which closes Friday, passed $370,000 with 51 bids as of today. Berkshire Hathaway CEO Buffet has auctioned off the lunch via eBay for the past 12 years. The highest winning bid of $3.5 million went to an anonymous person in 2012. An anonymous bidder won last year with $1,000,100. The lowest winning bid was $18,000 in 2001, before the auction moved online through eBay.We asked three past winners whether the most expensive lunch of their lives was worth it and here's what they had to say:Money manager Mohnish Pabrai of Pabrai Investment Funds, his wife, Harina Kapoor, and their children had lunch with Buffett at Smith & Wollensky's in New York in 2008. Pabrai of Irvine, California, and his best friend, Guy Spier, paid $650,100 in the 2007 eBay auction benefiting Glide.Pabrai called the lunch a "priceless" experience that "widely exceeded expectations.""If you were living at the time of Ben Franklin, Einstein, Gandhi or Teddy Roosevelt and had the opportunity to bribe them and sit down for a meal, would you do it? I think Buffett will go down in history in the same way," Pabrai, 49, told ABC News today. "I just found it interesting that he happens to be alive while I'm alive and is willing to take a bribe and sit down for a meal."Pabrai shared three pieces of Buffett's advice that he says have affected his life and that of his family:Pabrai recalls: "He said, 'You can live your life in two ways: with an outer scorecard - in which you care what other people think, or you can live your life with an inner score card.' He asked, 'Would you prefer to be greatest lover in the world but known as the worst, or would you prefer to be the worst lover in the world, but be known as greatest?'"Warren is completely and totally 'inner scorecard.' He doesn't care what other people think of many of his decisions and facets of his life. He does what he thinks is the right thing to do, even if, in the short term, it's unpopular."It's documented in books about him, but I sense that this inner-outer scorecard attribute is very important to him. It's an important trait he cares a lot about, and it has a huge impact on your life and how successful you are," Pabrai said.Pabrai also said lunch with Buffett, 83, has paid other dividends, including leading to a lunch with Berkshire Hathaway vice chairman Charles Munger and annual invitations to Omaha, Nebraska-based Berkshire Hathaway events."I think that's all part of his effort. He enjoys the lunch and he wants the people who bid that they got the better end of the deal," Pabrai said.Pabrai said Buffett takes innocuous questions and turns them into "learning opportunities," which, in turn, has helped Pabrai become a better investor.During the lunch, Pabrai asked what had happened to Buffett's former investing colleague, Rick Guerin, who, along with Munger, worked with Buffett in their early business days. Buffett talked about Guerin's high-risk investments that collapsed in the 1970s and forced him to sell his shares of Berkshire Hathaway."Warren went one step further. He said, 'Charlie [Munger] and I always knew we would get very rich. But we were not in a hurry. We knew we would get rich eventually. But Rick [Guerin] was in a hurry.' He went one step further behind that and said, 'Even if you are slightly above-average as an investor and spend less than what you earn, you can't help but get wealthy in your lifetime.'"Pabrai said that conversation was "seared in his psyche so strongly.""It illustrated to me that Warren's inner scorecard - the issue of not being in a hurry and being very patient is very core to who he is," Pabrai said.Pabrai said Buffett made clear at the start of the lunch that he had no other engagements and was willing to spend as much time with his guests as they liked. After three hours, it was Pabrai who ended the meal."Warren told my daughters, who were 10 and 12 at the time, that the single most important decision they'll make in their lives was who they will marry."As teenagers today, Pabrai's daughters still bring up Buffett's advice to him, which Pabrai said he appreciates as a father."I say, 'That's good.' Keep that advice front and center at that age," Pabrai said.Pabrai said his younger daughter encapsulated Buffett the best."I wasn't sure what the kids would think about three hours with Warren, though I'm a big fan. I asked my younger daughter her impression maybe 10 minutes after the lunch," Pabrai said."She said, 'He's just a kid.' I think that's the absolute best way to describe Warren. That is a key thing about him versus other humans. Most of us, as we grow up, we lose absolute innocence and fearlessness that we have as six year olds. We lose that. Warren still has that. He says he still only eats what he ate when he was five years old.""In the way he goes on about life -- the many facets -- he has the innocence of a kid and the enthusiasm as a kid," Pabrai said.Guy Spier, manager of Aquamarine Fund in Zurich, Switzerland, and his wife joined Pabrai and his family over lunch with Buffett in 2008."The most important thing I got from that lunch was learning Warren Buffett was not marching to anyone else's tune. He was marching to the sound of his own drummer," Spier, 48, told ABC News. "He wouldn't do one thing to increase the value of Berkshire Hathaway if it wasn't aligned with who he was."Though Berkshire Hathaway is one of the most successful companies in the world, Spier said he was impressed that Buffett "wasn't willing to sacrifice himself for it.""He has a very strong 'inner scorecard,' much stronger than mine would ever be," Spier said, adding that Buffett's "incredible mind" was something to behold in person, as opposed to watching him on television or at a large Berkshire Hathaway gathering.Spier also said he had to "see him in action" to understand how "futile" it was to try to be a version of Buffett.Six months after meeting Buffett for lunch, Spier said he made major life decisions, including letting go of a large portion of his staff and leaving New York City to move to Zurich."I hit a massive reset button in my life," said Spier, who describes further how the lunch affected his life in an upcoming book called "The Education of a Value Investor," out in September by publisher Palgrave Macmillan.Courtenay Wolfe, formerly of Salida Capital in Toronto, met Buffet after the firm won the 2009 auction with $1.68 million.As president and CEO of Salida at the time, Wolfe told ABC News today, "Lunch with Warren Buffet was a once in a lifetime experience.""I highly recommend the opportunity to anyone in the future that is bidding," she said. "The Glide Foundation is also an incredible charity; one of the most impressive I have seen. It is a very worthy cause that has a huge impact."I also recommend the winner take the time to go to San Francisco after the lunch to learn about the Glide foundation and all the benefits their winning bid helped fund."(The Glide Foundation, associated with Glide Memorial United Methodist Church and pastor emeritus Cecil Williams, serves low-income individuals and families in San Francisco.)