You love buying your shirts when they go on sale. And who can resist a buy-one-get-one-free offer? So when our stocks go on sale, why do we bemoan their low prices?

Smart investors like Warren Buffett and Marty Whitman love it when their stocks are suddenly selling at bargain-basement prices. For them, these companies become no-brainer buys.

The investors in the Motley Fool CAPS community also like a bargain. Below, you'll find five companies whose shares are selling at least 50% below their 52-week highs, but which still earn top five-star honors from our investor-intelligence database. Consider it a BOGO sale on stocks.

Stock

CAPS Rating
(out of 5)

% Off
52-Week High

Allis-Chalmers (NYSE:ALY)

*****

67%

China Security & Surveillance Technology (NYSE:CSR)

*****

55%

Eagle Rock Energy Partners (NASDAQ:EROC)

*****

68%

ION Geophysical (NYSE:IO)

*****

78%

TBS International (NASDAQ:TBSI)

*****

61%

Naturally, we want you to look a bit closer at these stocks before buying. You can get low-priced appliances in the dent-and-ding section of your home-remodeling superstore, but their quality might not be so good. Same thing here: Make sure there's nothing seriously wrong with the company before you plug it into your portfolio.

Securin' and surveillin'
In a world where security remains a real concern, highly rated CAPS All-Star dbbfool63 believes that China Security & Surveillance Technology gives the investor exposure to "international plays and being diversified in the security sector."

Five years ago, more than 600 cities in China were designated "Safe Cities" and were required to install and operate surveillance equipment. China Security & Surveillance Technology (CSST) is an approved vendor for the program, for which there are no dominant players locally yet, even if it considers Honeywell (NYSE:HON) and General Electric (NYSE:GE) as competitors. That could allow it to grab a good portion of the $6 billion to $12 billion the Chinese government is planning on spending for surveillance and safety equipment for the 2010 World's Fair in Shanghai.

There are two big risks investors need to be mindful of here. First, there are few recurring sources of revenue. Once one of these Safe Cities installs a CCST surveillance system and its DVR recording and monitoring equipment, there's little need to go back and make additional sales. The company will need to keep finding new customers, which brings us to the second risk.

To find those new customers, it is branching out to grab private-sector business. That tends to be lower-profit because of price competition, and management noted in its last conference call that gross margins suffered as a result of the smaller-scale projects. Yet these corporate contracts accounted for 58% of CCST's revenue in the last quarter, suggesting margins will continue to be under pressure.

CAPS member backtowhatworks thinks if it "can gain a controlling amount of market share via penetration and M&A," then it should be able to offset the margin weakness that comes with these opportunities.

To help offset that, China Security & Surveillance is extending its reach beyond Safe Cities and is looking at the numerous "e-cities" that are sprouting up across the country. It's wiring communities for integrated digital platforms that combine broadband communications infrastructure and platforms for multimedia and mass storage. CSST won two contracts in Haimen City and Nanjing this month, for which it will build the project, then transfer ownership to the government.

There seem to be plenty of growth opportunities for the surveillance technology leader to exploit, even if it does give you flashes of a creepy 1984 mentality at work in the country.

Have half a mind
It pays to start your own research on these stocks on Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made, all from a stock's CAPS page.

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Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.