Cigar Butt Investing
Benjamin Graham, the father of value investing was known for buying stocks on the cheap. Buffett called them cigar butt stocks.

These are stocks that are unloved. Stocks that do not offer sexiness. Stocks you cannot boast about to your friends for fear of being called crazy. These are the stocks that a homeless guy will pick up and give one last puff. The funny thing is, if you puff away at enough of these butts, you can make some generous profits.

Now you may be asking who on earth would buy such stocks, but back in the early days of Warren Buffett's career, these were the types of stocks he invested in. His most famous cigar butt purchase must be Berkshire Hathaway.

Low P/B Companies
The low PE screen to find cheap stocks is widely used and often referred to as a method to find cheap stocks, but I much prefer a low P/B screen as it is based on assets rather than GAAP earnings.