Here at Zacks, we focus on our proven ranking system, which places an emphasis on earnings estimates and estimate revisions, to find winning stocks. But we also understand that investors develop their own strategies, so we are constantly looking at the latest trends in value, growth, and momentum to find strong companies for our readers.Considering these trends, value investing is clearly one of the most preferred ways to find strong stocks in any type of market. Value investors use a variety of methods, including tried-and-true valuation metrics, to find these stocks.On top of the Zacks Rank, investors can also look at our innovative Style Scores system to find stocks with specific traits. For example, value investors will want to focus on the "Value" category. Stocks with high Zacks Ranks and "A" grades for Value will be some of the highest-quality value stocks on the market today.Ally Financial (ALLY) is a stock many investors are watching right now. ALLY is currently sporting a Zacks Rank of #1 (Strong Buy), as well as an A grade for Value.Investors should also note that ALLY holds a PEG ratio of 0.22. This popular figure is similar to the widely-used P/E ratio, but the PEG ratio also considers a company's expected EPS growth rate. ALLY's PEG compares to its industry's average PEG of 0.33.Finally, investors should note that ALLY has a P/CF ratio of 5.03. This data point considers a firm's operating cash flow and is frequently used to find companies that are undervalued when considering their solid cash outlook. This company's current P/CF looks solid when compared to its industry's average P/CF of 7.79. Within the past 12 months, ALLY's P/CF has been as high as 6.59 and as low as 2.02, with a median of 4.38.These are only a few of the key metrics included in Ally Financial's strong Value grade, but they help show that the stock is likely undervalued right now. When factoring in the strength of its earnings outlook, ALLY looks like an impressive value stock at the moment.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Ally Financial Inc. (ALLY): Free Stock Analysis Report To read this article on Zacks.com click here.