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.

Stock

CAPS Rating 
(out of 5)

% Off 12-Month High

A-Power Energy Generation Systems (Nasdaq: APWR) ***** 67%
Delta Petroleum (Nasdaq: DPTR) ***** 50%
Level 3 Communications (Nasdaq: LVLT) **** 50%

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
Along with concerns about the end of a supply agreement with General Electric for gearbox assemblies for wind turbines, you have to wonder about A-Power Energy Generation Systems' Spinning Star wind farm project in Texas.

For the project, which has several backers, financing had to be in line by the end of last year, otherwise partners could back out, but that deadline has come and gone with no announcements. Nor has anyone said they're leaving just yet. A-Power has aligned itself with both politically connected players and top congressional leaders -- no one less than Senate Majority Leader Harry Reid -- to get the project off the ground. While denying there's any quid pro quo, A-Power agreed to build a manufacturing plant in Nevada and secured funding from the Department of Energy.

A-Power is also getting contracts from Chinese companies, such as the two it recently signed worth a combined $56 million, that ought to help overcome the crushing blow it suffered when it reported earnings and cut guidance last month. But American Superconductor (Nasdaq: AMSC) is gaining more Chinese customers, too.

Would you like to decide whether A-Power can overcome these obstacles? Add it to your watchlist, where all the Foolish news and analysis about this stock is gathered for you in one place.

A reserve player
It has been a long walk down for Delta Petroleum after its Washington state Gray well failed last year. The company has also labored under the resignation of its CEO, failed financing deals, and asset sales to lessen its debt load.

Much of the industry is bouncing back, though, with EOG Resources (NYSE: EOG) up 11% over the past month and Chesapeake Energy (NYSE: CHK) almost 20% higher. Delta might be ready to recover, too. It was able to record a third-quarter profit compared with a loss in the year-ago period, and it was able to secure a $100 million line of credit.

CAPS member DannyNOLA finds the independent exploration and production company to be so depressed right now that it's ripe for the picking.

Natural gas prices-LOW, DPTR price-LOW, Interest rates-LOW....come on large players, just buy DPTR finance it with a cheap loan, and wait for gas prices to go higher.

Let us know what you think on the Delta Petroleum CAPS page.

On the level
Level 3 Communications also carries a lot of debt, but the telecom services provider showed it was still nimble enough to steal Netflix from rival Akamai Technologies (Nasdaq: AKAM). These kinds of relationships are fluid, but Level 3 is confident enough that it reaffirmed its fourth-quarter guidance and said its core network services business should grow from the previous quarter's numbers.

CAPS member mosese likes what the Netflix deal means for Level 3, and CAPS member edwatki says the company remains innovative.

LVLT continues to have considerable new business, and introduce new meaningful products. CAPS rating has gone from 3 to 4 this past week. Routers rating has improved. Stock price went up $0.13/share last week.

Add the telecom services provider to Fool.com's free portfolio tracker to keep up with its progress.

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