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

R.R. Donnelley & Sons (NYSE:RRD)

*****

1.86

(19.7%)

American Capital (NASDAQ:ACAS)

****

1.63

(84.8%)

International Rectifier (NYSE:IRF)

***

1.87

(43.2%)

Tellabs (NASDAQ:TLAB)

***

1.69

(26.1%)

Blockbuster (NYSE:BBI)

*

0.39

(84.5%)

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 140,000-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 16 stocks that CAPS found hiding in the weeds, convenience store operator The Pantry (NASDAQ:PTRY) intrigues me this week. The details:

Metric

The Pantry

Recent price

$16.14

CAPS stars (5 max)

****

Total ratings

184

Percent bulls

91.3%

Percent bears

8.7%

Price-to-book

0.82

ROE

15.6%

% Above 52-week low

21.3%

Sources: CAPS, Yahoo! Finance. Data current as of Sept. 18.

The thesis for The Pantry isn't much different from that for rival Casey's General Stores (NASDAQ:CASY). Fools who like Casey's like it because its gas and grocery convenience stores are often the primary (and sometimes only) options for small-town U.S. residents.

"Earnings projections are on the way back up, and this stock is far below the P/E of its industry peers," wrote CAPS investor physicsisphun in June. "On the next one or two earnings cycles, I think it will bounce quite significantly."

A $0.45-per-share earnings miss in its last quarterly report has held this stock in check, but at five times earnings, it now trades as if growth won't return. I wouldn't bet on that.

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

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