NEW YORK ( TheStreet) -- Shares of Amazon.com ( AMZN) were slipping in late trades on Thursday after the online mega-retailer came up short in its latest quarter despite a year-over-year sales increase of nearly 30%. The Seattle-based company reported a net loss of $274 million, or 60 cents a share, for the third quarter with sales totaling $13.81 billion. In the same period a year earlier, Amazon earned $63 million, or 14 cents a share, on sales of $10.88 billion. The latest results reflect a loss of $169 million, or 37 cents a share, related to asset impairment at its LivingSocial unit. The average estimate of analysts polled by Thomson Reuters was for a loss of 8 cents a share in the September-ended period on revenue of $13.92 billion. "Our approach is to work hard to charge less. Sell devices near breakeven and you can pack a lot of sophisticated hardware into a very low price point," said Jeff Bezos, Amazon's founder and CEO, in a statment. "And our approach is working - the $199 Kindle Fire HD is the #1 bestselling product across Amazon worldwide. Incredibly, this is true even as measured by unit sales. The next two bestselling products worldwide are our Kindle Paperwhite and our $69 Kindle. We're selling more of each of these devices than the #4 bestselling product, book three of the Fifty Shades of Grey series. And we haven't even started shipping our best tablet -- the $299 Kindle Fire HD 8.9 ships November 20." This approach was evident in Amazon's operating margins, which came in at a negative 0.2%, declining for a third straight quarter. The stock was last quoted at $219.80, down 1.4%, on extended volume of more than 3 million, according to Nasdaq.com. For the fourth quarter, Amazon forecast between an operating loss of $490 million and an operating profit of $310 million with sales projected between $20.25 billion and $22.75 billion. Coinstar ( CSTR) was under pressure after the bell, falling more than 5%, after the company missed on revenue in its latest quarter and gave a weak guidance for the final three months of 2012. The operator of Redbox DVD rental kiosks reported core earnings of $1.26 a share for the third quarter on revenue of $537.6 million vs. Wall Street's consensus view for a profit of $1.15 a share on revenue of $557 million.