GOLDMAN: Here are the 13 cheapest stocks in the market

The S&P 500 gained a meager 4 points in the first half of 2015, effectively delivering a 0% return for investors.

Goldman Sachs's David Kostin, however, sees better gains ahead.

"We expect S&P 500 will return 6% during the next 12 months (4% price, 2% dividends)," Kostin said.

In a new report, Kostin identified the 40 stocks in the market offering the most upside relative to Goldman Sachs analysts' price targets.

We've ranked the 13 stocks with possible upsides of over 35%. Find them below, listed from least to most potential.