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

Lexicon Pharmaceuticals (NASDAQ:LXRX)

****

62%

Melco Crown Entertainment (NASDAQ:MPEL)

****

51%

Popular (NASDAQ:BPOP)

****

60%

USEC (NYSE:USU)

*****

52%

Vaalco Energy (NYSE:EGY)

*****

52%

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 in to your portfolio.

Take two; they're small
The Macau casino market is supposed to be the gambling hall that's going to turn around an industry. Driven to distraction by the recession, Las Vegas Sands (NYSE:LVS) and Wynn Resorts (NYSE:WYNN) both placed major bets on opening casinos in the only Chinese city where gambling is legal, by launching IPOs on the Hong Kong stock market.

The reception, however, looks like it has petered out. Wynn's overseas stock has fallen by 5% since its IPO, and Sands fell 10% on the first day of trading. Lady Luck isn't smiling on the casino operators, either. Melco Crown Entertainment, however, is a pure play on the Macau market, but despite a 70% surge in third-quarter revenue, losses for the Chinese casino operator also widened to $39.5 million from $21.1 million in the year ago period.

Looking at Melco's opportunity from a technical-analysis perspective, CAPS member akclide sees the gambling house performing better than either Wynn or Sands.

Technically it made a triple bottom on a 6 month chart, Moving averages are trying to converge. P/s Ratio is actually better than that of LVS and WYNN, both direct [competitors]. LVS sand IPO coming out will also give boost 1st stop $5 which is approx 18% return. I expect hold time between 30-60 days.

Nothing to be irritable about
You might not want to admit to having irritable bowel syndrome, but sufferers and investors won't be cramped by Lexicon Pharmaceutical's treatment, which reported positive results in a key clinical trial. The drug developer said patients taking 1 gram of its therapy four times a day had less pain and discomfort than did those who took a placebo.

IBS -- a surprisingly little-understood condition -- afflicts 20% of the adult population, according to the National Institute for Health, and is accompanied by abdominal pain, bloating, and discomfort. Lexicon's LX1031 relieves those symptoms without causing constipation, which otherwise might be a case of the cure being just as bad as the disease.

With a steady flow of other treatments due to report results over the coming year, however, CAPS member topsecret09 thinks Lexicon won't get backed up if one of them should end up stumbling: "With many key trial results being announced over the next 12 months, this biotech seems like a logical addition to [anyone's] portfolio, with a fairly low degree of risk at this currently depressed stock priceĀ of $1.63."

Lexicon is still in early development on a Type 2 diabetes treatment, as well as ones for rheumatoid arthritis and carcinoid syndrome. At more than 17 times sales, the pharmaceutical's shares seems a bit gaseous, particularly as revenues in the most recent quarter collapsed 72% from last year.

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.