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 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 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 (5 max)

% Off 52-Week High

Applied Materials (NASDAQ:AMAT)

*****

55.3%

Foster Wheeler (NASDAQ:FWLT)

*****

73.4%

Minefinders (NYSE:MFN)

*****

65.8%

National Oilwell Varco (NYSE:NOV)

*****

76.2%

United States Natural Gas Fund (NYSE:UNG)

*****

62.4%

Source: Motley Fool CAPS.

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 three, they're small
If the rumored value of the infrastructure stimulus package that the incoming Obama administration is discussing proves to be a reality, engineering and construction firms like Foster Wheeler and Jacobs Engineering (NYSE:JEC) ought to reap the rewards. Further, if the administration is able to keep its word that the package will be free of the typical earmarks politicians love to saddle such spending plans with, then most of the money may actually get to the construction projects as planned.

That sort of pristine spending has investors thinking that Foster Wheeler is significantly undervalued and doesn't account for the potential influx of revenue. CAPS member GreatDruid says the stock is valued only on the current status of infrastructure. "Large infrastructure projects have taken a hit - [Foster Wheeler] is poised to grow after the recession has bottomed out and may be in the running for $$$ for stimulus of large project spending."

Has the dramatic decline in the price of oil doomed the ability of alternative energy projects to get off the ground? Just as certain exploration and drilling projects can no longer be justified below a particular price point for oil, some projects like those in solar energy may no longer be economically feasible. Yet some investors think that analysis is already priced into stocks like Applied Materials, which also makes equipment for producing thin-film panels. There may be hope that it has bottomed out already.

CAPS member unvrsldeflation thinks that if a tech rally does eventually materialize, Applied Materials will bounce:

It's tough to say if Applied Materials is as beaten down as it can be. It is my opinion that they tend to trend along with broader conditions. What is interesting here is that the oil price drop and what it has done to their solar aspirations is probably priced into the stock. They could get an Obama bounce as well as a lift from the tech rally (if there is going to be a tech rally).

Minefinders made the switch from exploration to production with the first pour from its Dolores mine last month, which is expected to produce 1.7 million ounces of gold and 64 million ounces of silver over the mine's 15-year life. If management's projection that it can be a low-cost, mid-tier gold and silver producer by early next year comes true, Yamana Gold (NYSE:AUY) and other low-cost producers may be given a run for their money. CAPS member coregonus thinks Minefinders is worth keeping an eye on over the long haul. "Long term gold exploration, this smaller company has good resources and is not overextended. I am no prospector myself, but submit this one to watch."

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.

On Jan. 12, 2009, Fool co-founder David Gardner, Jeff Fischer, and their Motley Fool Pro team will accept new subscribers to their real-money portfolio service. Motley Fool Pro is investing $1 million of the Fool's own money in long and short positions in a range of securities, including common stocks, put and call options, and exchange-traded funds (ETFs). They also incorporate proprietary CAPS "community intelligence" data into their research. To learn more about Motley Fool Pro and to receive a private invitation to join, simply enter your email address in the box below.

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. National Oilwell Varco is a Motley Fool Stock Advisor pick. The Motley Fool's disclosure policy knows where the bodies are buried.