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

Stock

CAPS Rating
(out of 5)

% Off 52-Week High

Cornerstone Therapeutics (NASDAQ:CRTX)

****

59%

Energy Partners (NYSE:EPL)

****

76%

K-SEA Transportation Partners (NYSE:KSP)

*****

57%

NPS Pharmaceuticals (NASDAQ:NPSP)

***

55%

Progrenics Pharmaceuticals

****

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.

Take two, they're small
No doubt it looks like K-SEA Transportation Partners pulled a bunch of bonehead moves after its fiscal first quarter earnings report when it suspended its dividend -- one of the prime attractions of this master limited partnership -- and warned that it may breach financial covenants. Yet its financial woes are directly tied to the state of the petroleum industry, and until recently that hasn't looked particularly favorable.

K-SEA operates a fleet of tugs and barges servicing oil producers like ExxonMobil (NYSE:XOM) and ConocoPhillips (NYSE:COP). Demand for tank vessels is driven by demand for oil, including gasoline and heating oil. Considering that overall demand for these products has been off dramatically, and stockpiles have been high, it's not surprising that K-SEA has experienced difficulties.

Yet crude inventories have been falling lately. Stockpiles were down by 2 million barrels two weeks ago and dropped another 3.7 million barrels last week. And while still high, gasoline inventories rose less than what analysts had been anticipating. CAPS member unlearned views K-SEA's current price as unsustainable with broad economic trends moving in its favor.

As long as we need heating oil or gas for our cars this company will be safe. It works with some of the largest oil companies lugging over 150 million barrels of oil last quarter. It has reduced its fleet last quarter and has seen demand increase over the past two quarters, The company is now profitable, and should be able to hold through next year.
With some of it's clients purchasing and researching algae fields for the alternative green fuel. The algae fuel will still need to be transported by someone and who better then the company that they already work with.
The company cut its dividend and the stock tanked, which now makes the yield over 16%. This price will not last.

With some 93% of CAPS investors rating K-SEA to still outperform the market, they seem to believe it can rebuild itself. Head over to K-SEA Transportation Partners' CAPS page and let us know if you think this crude assessment is valid.

No prescription for relief
With a handful of pharmaceutical and biotech companies on our list this week, it points to the difficulty the industry is facing in coming up with hit drugs to bring to market. As a result, investors have bid down their shares.

NPS Pharmaceuticals, for example, has said it is experiencing slower-than-expected enrollment in one clinical trial, though it now expects to achieve full enrollment by mid-2010. In the meantime, it has been subsisting on royalties received from Amgen (NASDAQ:AMGN) for its treatment of non-cancerous tumors in the parathyroid gland.

NPS is not alone in having a harder time of it these days. Cornerstone Therapeutics found itself needing a cash infusion and sold a majority stake to an Italian pharmaceutical company. While revenues grew in the latest quarter, much of that came as a result of acquisitions it made over the last year. Adding to its woes was a letter from the FDA warning it had distributed drugs without approved applications for them, although Cornerstone says it no longer is selling those products.

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 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.