Cheap stocks can get cheaper. They often do.

Unfortunately, "cheap" is a relative term. Precious few stocks that trade for low price-to-earnings ratios or below book value are real bargains. They look enticing but are instead value traps -- stocks that deserve the multiples for which they trade, and punish the garbage-grabbers who buy them.

But don't take my word for it. Here are five "cheap" stocks that trapped bargain-hunting prey:

Company

CAPS Stars
(Out of 5)

2004 Price-to-Book Ratio

Return Since

E*TRADE (NASDAQ:ETFC)

****

1.91

(88.1%)

Flextronics (NASDAQ:FLEX)

****

1.23

(47.4%)

American Capital (NASDAQ:ACAS)

***

1.58

(85.9%)

Saks (NYSE:SKS)

**

0.84

(40.5%)

Ambac Financial (NYSE:ABK)

*

1.71

(98.4%)

Sources: Motley Fool CAPS, Capital IQ, Yahoo! Finance.

Watch out!
How can you avoid value traps like these? My favorite method is borrowed from professor Aswath Damodaran. In his book Investment Fables, Damodaran counsels investors to measure low price-to-book stocks by their returns on equity (ROE).

Makes sense to me. Book value is shorthand for equity. A low price-to-book stock is priced as if management won't produce high returns from the equity capital afforded it. Find a stock that defies this maxim -- a stock with an above-average and rising ROE -- and you may have found a bargain.

A machete for when you're in the weeds
Our 135,000-member-strong Motley Fool CAPS database is a great place to start your search. I ran a screen for well-respected stocks trading for less than twice book value, and whose returns on equity were 10% or more. Qualifiers were also trading no more than 25% above their 52-week low, leaving plenty of room for further gains.

Of the 25 stocks that CAPS found hiding in the weeds, Teleflex (NYSE:TFX) intrigues me this week. The details for this Motley Fool Inside Value pick:

Metric

Teleflex

Recent price

$45.73

CAPS stars (out of 5)

*****

Total ratings

84

Percent bulls

91.7%

Percent bears

8.3%

Price-to-book

1.24

ROE

20.1%

% Above 52-week low

22.9%

Sources: CAPS, Yahoo! Finance.
Data current as of Aug. 17, 2009.

Teleflex is an old pick for Inside Value­. Advisor Philip Durell singled out the stock in the August 2006 issue of the newsletter. Fortunately, the thesis is timeless: Teleflex combines modest organic growth with small yet strategic acquisitions, resulting in bountiful free cash flow used for, among other things, generous dividend payments.

The numbers are worth eyeballing. From 1997 to 2007, for example, Teleflex increased its dividend payment 12.38% annually, to $1.25 per share. This year, the company is on track to distribute $1.36 for every share held, up another 8.8% from two years ago.

Contrast that with General Electric (NYSE:GE), a much larger industrial conglomerate, which recently reduced its dividend payment to cut costs. Impressive, no? Mix in a commitment to invest only in its most profitable business units, and Teleflex begins to look like a very attractive long-term holding.

But that's just my take. Would you buy shares of Teleflex at today's prices? Let us know by signing up for CAPS today. It's 100% free to participate.

More bargain basement Foolishness:

Want further guidance? Get 30 days of free access to the Fool's Inside Value service, which spotlights stocks that Mr. Market has put on sale. Teleflex is a current pick. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Tim Beyers is also a member of the Motley Fool Rule Breakers stock-picking team. Tim didn't own shares in any of the companies mentioned in this article at the time of publication. Check out his portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. The Motley Fool is also on Twitter as @TheMotleyFool. Its disclosure policy is a bargain at any price.