Stock buyers, like most shoppers, try to pay a little but like to get a lot. To do so, they often rely on measures that compare the cost of a company to its prosperity. The price-to-earnings ratio is easily the most popular of these measures, but its less-used sibling, the price-to-sales ratio, appears to be a better predictor of stock returns.

That might seem odd. Just about any company can slash prices to move merchandise, resulting in plentiful sales, but only successful companies sell at prices that far exceed their costs, resulting in strong earnings. You d think earnings would be the more telling of the two measures. However, long-term studies of the predictive power of financial measures, like ones authored by money managers James O Shaughnessy and Kenneth Fisher, suggest stocks with low price-to-sales ratios tend to produce higher returns than ones with low price-to-earnings ratios. Perhaps that s because earnings are easily skewed by one-time events or swings in the business cycle, while sales tend to be more stable.

Investors who search for stocks with low price-to-sales multiples should keep a few things in mind. First, make comparisons among industry peers. It wouldn t help much to compare a mass merchant with a specialty retailer, as the former is expected to bring in far more sales, but with smaller profit margins. Second, avoid withering companies by searching also for healthy, or even accelerating, sales growth. Third, review search results for companies that recently bought rivals, resulting in the appearance of a sudden pick-up in sales, but without the full benefit.

Below are listed three large companies with price-to-sales ratios that are below their industry averages, and sales growth that recently quickened. Also, each pays a dividend.

Boeing

Price-to-sales: 1.4

Last year, Boeing s sales increased by 12% but earnings per share fell by half. Both numbers mislead, though. Sales rose in part because a labor strike the year before had crimped them. Earnings suffered because of production delays in the company s new fuel-efficient 787, which is now making test flights. Temporary setbacks aside, Boeing s new plane is already in strong demand, and an ongoing economic recovery bodes well for future orders. Analysts expect the industry-wide number of commercial jet deliveries to reach more than triple 2009 s weak pace by 2014.

The Gap

Price-to-sales: 1.6

Gap shares have more than doubled in price since March 2009, when the stock market bottomed. That likely reflects not only a cautious increase in consumer spending, but also management s efforts to turn the underperforming retailer around. Last year, the company closed more than two stores for each it opened, with a focus on eliminating North American Gap and Old Navy locations with shrinking sales. As a result, February sales at longstanding stores were up 3% from a year ago, versus a 12% decline in February 2009. The company is debt free and holding cash equal to about 16% of its stock market value. Its board recently boosted the dividend to 40 cents a year from 34 cents, which makes for a yield of about 1.7%.

Lockheed Martin

Price-to-sales: 0.7

If America is about to cut its military spending, there was little evidence of it in President Obama s proposed defense budget, released in February. It called for a 3.4% increase in baseline spending, and plenty of supplemental cash. Sales for Lockheed Martin, which makes fighter planes, missiles, spy satellites and more, are expected to increase 4% this year and next. That s not blazing growth, but then, the company s stock seems priced for low expectations. Shares trade at just 11 times this year s estimated earnings -- a discount of about one-third to the broad stock market. The company s dividend yield, meanwhile, is 3% -- half again as large as the market s yield.