EBay Inc., the world’s largest online auctioneer, sales could be lowered as its customers turned to Google Inc. and other sites to buy and sell goods. Fourth-quarter revenue expected to grow 25 percent to $1.67 billion, may be the slowest increase in last seven years. Shares of EBay declined 70 cents, or 2.4 percent, to $28.62 in NASDAQ Stock Market, touching a three-month low. The number of listings grew 13 percent in the fourth quarter as consumers and sellers used the site, but survey shows that EBay’s best customers are spending less on each purchase. Transaction revenue per active user has dropped 7 percent. EBay brought PayPal in 2002 for $1.18 billion in stock to lessen its reliance on auctions by collecting commissions from buyers sending payments by e-mail. To fend off competition from Google Inc.’s CheckOut service, PayPal in November offered as much $100 million in holiday rebates and free shipping.