OMAHA, Neb. (AP) -- The price of a private lunch with Berkshire Hathaway's (NYSE:BRK-A)(NYSE:BRK-B) Warren Buffett has already topped $500,000, and the online auction to raise money for a California homeless charity continues all week.

The eBay auction began Sunday with a $25,000 opening price. By Tuesday, eight bidders had driven the price up to $500,100.

That's an impressive price for lunch, but last year's winner paid $3,456,789. The Glide Foundation, which provides social services to the poor and homeless in San Francisco, counts on the auction proceeds as part of its $17 million annual budget.

Buffett's advice is sought because of his investing success and his decision to give most of his fortune to charity.

Bidding continues until 9:30 p.m. Central Friday, and prices usually soar near the end of the event.

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