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 three 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.

Company

CAPS Rating
(out of 5)

% Off 12-Month High

AgFeed Industries (Nasdaq: FEED)

*****

55%

AK Steel (NYSE: AKS)

****

50%

National Bank of Greece (NYSE: NBG)

****

73%

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
Whoa! Maybe that explains the drop suffered by Chinese agriculture stocks like AgFeed Industries, China Green Agriculture (NYSE: CGA), and American Dairy (NYSE: ADY). They started out the month down a collective 30% from the beginning of the year, leading many to believe they had been oversold, but market analysts at the Conference Board said today there was a calculation error in the computation of leading Chinese economic indicators. Rather than a robust 1.7% increase in April, the numbers really showed a stagnant 0.3% rise. China's economy stalled out months ago.

The Chinese market reacted negatively to the report, with the CSI 300 falling more than 4.5% overnight. Evidence is building that China can't defy gravity (and reality) forever, and its economic engine is slowing dramatically. The Industrial and Commercial Bank of China said growth in new loans fell more than 39% through the first half of the year, although much of that could probably be attributed to more stringent loan standards.

But do declining economic numbers translate into lower demand for hogs, particularly in a country that is the world's biggest producer and consumer of pigs? CAPS All-Star jamespeer doesn't think so, believing its operational performance has still been exceptional.

A closer look into the numbers tells us why this is such a highly rated stock. 144% revenue growth and 35% EPS growth over the last 3 years. $36.6M cash on the balance sheet with very little debt. Book value p/share is $3.58 (SP is $3.25 at time of writing), and [AgFeed] is trading at a significant discount to 2010 earnings with a forward P/E of just over 7. The only problem with chinese stocks in general is that management tends to consistently over-promise and under-deliver. But with significant growth opportunities in China's hog and animal feed markets, [AgFeed] offers tremendous value at these prices...

A little private time
One company likely to be affected by what happens in China is steel producer AK Steel. Iron ore prices are skyrocketing this year, with prices for ore arriving at Chinese ports already 21% higher than they were at the start of the year. Analysts expect they could nearly double by year's end.

Although some smart Fools think efficient cost controls will ultimately benefit the steelmaker, AK Steel was counting on only a 30% hike in ore prices beyond its first- quarter results. Because it wasn't even able to forecast what its earnings might be this quarter because of the uncertainty surrounding pricing, profits could be pinched if those prices go much higher. With about 70% of steelmaking costs tied to raw materials and energy, steel producers like U.S. Steel (NYSE: X) -- which is more vertically integrated and owns a significant portion of its supply -- ought to advance furthest in this situation.

With AK Steel's stock visiting these depressed levels, CAPS member stockafella thinks it could be set up as a takeover candidate.

[AK Steel] should be a takeover target with a price to book well below the industry average. Their price to sales is so far below the industry average it is ridiculous. At this price(below $17) it should be attractive as a takeover in an industry that is hungry for consolidation.

With friends like these
And obviously it's not just China's economy that's flatlining, but all of Europe, too. Just when we thought the European Union had staved off default in Greece, Spain looks like it's stumbling toward the same precipice. Sure, National Bank of Greece has been decimated by concerns about a default; now it looks like Banco Santander (NYSE: STD) could run into trouble as its home country's economy unravels. With Europe's central bank ending a program extending liquidity to Spain's troubled banks, the country's sovereign debt problems could snowball.

Santander's stock opened 6% lower today, while National Bank of Greece started down 5%, but CAPS member jbobolpc says it's important not to count the Greek bank out.

[National Bank of Greece] has a pretty healthy balance sheet and remains profitable despite the woes of the Greek Gov.

Share your thoughts on the National Bank of Greece CAPS page.

Have half a mind
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China Green Agriculture is a Motley Fool Global Gains selection. The Fool owns shares of China Green Agriculture. Try any of our Foolish newsletter services today, free for 30 days.

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