Although the papers have not yet been signed, Internet auctioneer eBay Inc. is expecting to seal the deal on purchasing StubHub Inc. for about $300 million in cash on either Wednesday or Thursday. San Francisco-based StubHub is an online ticket reseller that is said to be one of America"s fastest-growing companies. The 6-year-old privately held company thrives by charging a 15% fee to those selling tickets and a 10% commission to buyers, often reselling tickets above their face value. Ebay failed to buy the company in 2002, for $20 million.