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 cry about 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 which still earn top honors from our investor-intelligence database. Consider it a BOGO sale on stocks.

Stock

CAPS Rating

% Off 52-Week High

American Oriental Bioengineering (NYSE:AOB)

*****

53%

Constellation Energy (NYSE:CEG)

*****

78%

Universal Display (NASDAQ:PANL)

*****

74%

Vaalco Energy (NYSE:EGY)

*****

53%

Valero (NYSE:VLO)

****

74%

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
Considering that Warren Buffett typically only buys a company when he sees there's a large margin of safety (and a chance to take advantage of the terms he can negotiate), it seems doubtful that Berkshire Hathaway (NYSE:BRK-A) (NYSE:BRK-B) will back out of the deal to buy Constellation Energy. The $26.50-per-share offer Berkshire made back in September has Constellation shares trading in the mid-20s. The market obviously believes Berkshire will have to lower its price somewhat, since Constellation trades at an 11% discount to the buyout price. That arbitrage opportunity is attracting CAPS member Schmacko:

Bought some today at $22.75. Assuming the takeover deal goes through (cash deal @ $26.50/share) that's a roughly 16.5%, which in today's market is nothing to shake a stick at. Their annual dividend yield is currently over 8%. The next payment isn't until January, but with how long mergers take I wouldn't be suprised if I got to collect at least one payment while I wait, which bumps the total return up another 2% or so.

The volatility in the energy markets have been playing havoc with the likes of refiners like Valero and Tesoro (NYSE:TSO), which managed to escape significant damage from Hurricanes Ike and Gustav only to be buffeted by the desperate drop in demand for oil. Given the uncertainty currently gripping the economy and the markets, Valero's decision to conserve cash and cut back on capital expenditures seems to make sense. While that might cost it share if others don't follow its lead, the choice also means it will still be able to react when conditions improve. CAPS member Ralph124c feels there's enough excess demand internationally to keep Valero refining:

While the economies in China, India and Europe are all belching along with the US, there is enough excess demand to keep refiners busy. The differential between gasoline/diesel prices in Europe and the US is proof enough of that.

CAPS member leaderoftheback felt earlier this year that Motley Fool Rule Breakers recommendation Universal Display possessed interesting OLED-TV technology that could pay off in the future, but without posting earnings, it was too risky for him to touch:

No skin in this game as they have no earnings (which is against my rules of ownership), but I find the technology compelling. In the long run, it is technologies such as this, those that reduce resource use ("reduce" comes first in "reduce-reuse-recycle" for a reason) will lead us out of this dark tunnel. Will [Universal Display] be part of that procession? I have no idea, but if they start posting earings, I'll jump in.

Unfortunately, UD did nothing to help that cause this past quarter, though it continues to offer tantalizing tidbits about what the future can hold.

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.

American Oriental Bioengineering is a Motley Fool Hidden Gems pick. Berkshire Hathaway is an Inside Value selection as well as a Stock Advisor recommendation. Universal Display is a Rule Breakers pick. The Fool owns shares of Berkshire Hathaway and American Oriental Bioengineering. Try any of our Foolish newsletters 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 here. The Motley Fool has a disclosure policy.