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 or Marty Whitman love it when their stocks are suddenly selling at bargain-basement prices. For them, these companies become no-brainer buys.

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

Stock

CAPS Rating (Out of 5)

% Off 52-Week High

Alvarion (NASDAQ:ALVR)

*****

65%

American Oriental Bioengineering (NYSE:AOB)

*****

66%

Foster Wheeler (NASDAQ:FWLT)

*****

70%

United States Natural Gas (NYSE:UNG)

*****

79%

Vaalco Energy (NYSE:EGY)

*****

56%

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 in to your portfolio.

Take two; they're small
Although it remains well below the peaks climbed of last year, natural gas has rebounded off its recent lows. The June NYMEX contract at $3.97 per million BTUs, for example, is up over the six-year lows reached with the April contracts, but they're considerably beneath the $10.553 per MMBTUs it hit one year ago. Despite fears that the exchange-traded fund United States Natural Gas is behind the rising prices, there are other factors that might be pushing natural gas prices higher, even if inventories are at record levels.

Baker Hughes (NYSE:BHI), for example, reported that its natural gas rotary rig count fell to 728 rigs -- also a six-year low. A lower rig count will ultimately lower production, and that's what  concerns CAPS All-Star member rdpatton, who believes the lower count will be the key driver in pushing this ETF higher.

Natural gas is in a major trough. Huge number of rigs have been laid down. It is a "cleaner" fuel than coal and we have lots of it in the US. As economic activity picks up along with inflation this will double within a year or two.

Strong medicine
Even with first-quarter nutritional-product revenues growing by 29%, prescription-drug revenue growing 15%, and the over-the-counter drug sector of its business essentially unchanged, traditional Chinese medicine manufacturer American Oriental Bioengineering still fell short of analyst expectations on both revenues and profits.

The recession in China has no doubt caught up with the supplements company. And while top-line growth was 13% excluding the impact of the distribution business -- which it didn't have last year -- that figure represents a sharp decline from previous growth rates. Still, at a 66% compounded annual revenue growth rate over the past five years, any company would have a hard time maintaining the torrid pace AOB had been on. Tongjitang Chinese Medicines (NYSE:TCM), in comparison, though public for a shorter period of time, has achieved only a 9% CAGR over the past three years.

CAPS All-Star ChinaChaChing is unfazed and believes AOB has remained largely unscathed by the recession.

AOB, which focuses on plant-based medicine in China, is very strong financially, has been steadily expanding cash flow and earnings for years, and has a wide range of pharmaceutical products, OTC drugs and nutraceuticals to market to China. AOB ought to grow in tandem with China's economy once a proper economic recovery takes place. I am confident of this because AOB remains fundamentally unchanged by the crisis, still has over 60 products to market to the burgeoning Chinese population, and has a good relationship with the Chinese government (the State Food and Drug Administration has approved all 60 of their products). AOB is a bargain at this price methinks!

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.

Sign up today for the completely free service, and tell us whether these stocks are twice as good at half the price.

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Fool contributor Rich Duprey has no financial position in any of the stocks mentioned in this article. You can see his holdings. Test-drive the Motley Fool's full-size disclosure policy.