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 that 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

Allis-Chalmers Energy (NYSE:ALY)

*****

56%

Eagle Rock Energy Partners (NASDAQ:EROC)

*****

81%

ION Geophysical (NYSE:IO)

*****

72%

ReneSola (NYSE:SOL)

****

50%

United States Natural Gas (NYSE:UNG)

****

64%

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
The disconnect between natural gas and oil prices means bird watchers are seeing more black swans these days, but other factors are also diverting from historical norms. For example, natural gas supplies have reached record levels since the government began tracking inventory more than 30 years ago, despite drillers like Chesapeake Energy (NYSE:CHK) and Suncor Energy (NYSE:SU) selling production assets. Nationally, natural gas rig counts have been cut in half since last year

Yet traders last week were hoping that a colder than normal winter would cause a spike in demand, so they bid natural gas prices up. With supplies approaching the country's storage capacity, however, producers might end up dumping more onto the market, making prices lower still. Perhaps that explains why stocks of gas producers have been soaring. Chesapeake's shares are up nearly 70% year to date, while Gulfport Energy has more than doubled. XTO's shares are up 11% since the beginning of the year.

Exchange-traded fund United States Natural Gas, whose share price is down by half since January, isn't participating in the recovery. The fund stopped issuing shares back in July while regulators debated limiting the size of positions it could hold as a means to curtail speculation. Though the ETF began issuing shares again last week, it would seem it's still fraught with risk.

United States Natural Gas has been trading at a premium to the underlying assets it holds, but that premium should narrow now that the fund is issuing shares again. CAPS All-Star bg11235 writes that with inventories overflowing, prices will fall further, which ought to bring the ETF down with them.

TSIF notes that while many producers shut down because it just wasn't profitable to continue production, the bump in pricing for natural gas will have them opening the floodgates once again.

Some people see the 18% increase in Natural Gas prices a long overdue correction. Personally, from my readings, there is still a serious glut of natural gas. Many providers had turned the spigots off as it was costing more to pull it from the ground and store it than it was worth. This correction will cause most of the spigots to be reopened. Within weeks, if not days, the glut on the market will flood the system again. The bottom might not be where it was in early September, but it's below where it speculated up to.

Chesapeake Energy CEO Aubrey McClendon says that while the industry can survive with natural gas priced at $4 per million British thermal units, there won't be growth at those levels. But he says that while he hadn't been curtailing production to bail everyone else out, he sees everyone being forced to cut back soon enough, suggesting there will be more pain before the recovery arrives.

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.

Chesapeake Energy is a Motley Fool Inside Value pick. The Fool owns shares of Chesapeake Energy. 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.