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

Callon Petroleum (NYSE: CPE) **** 71%
EnerNOC (Nasdaq: ENOC) **** 54%
FormFactor (Nasdaq: FORM) ***** 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 into your portfolio.

Take two, they're small
Now that the Obama administration is ever so slowly starting to permit both drilling and exploration again in the Gulf of Mexico, there may be an opportunity for some smaller outfits to start getting in on the action. Unlike a company such as Hercules Offshore (Nasdaq: HERO), whose operations were closely tied to the Gulf, Callon Petroleum was fortunate to have onshore assets that at the height of the Gulf disaster it was able to switch its capital spending plan toward.

The change in outlook helped Callon for a while, and its stock recovered from its lows, but management's decision back in February to tap the equity markets to raise cash signaled to investors that maybe the share price had peaked.

ATP Oil & Gas (Nasdaq: ATPG) also had to bide its time while the "permitorium" was in effect, but some smart Foolish analysts see the stock still being a two-bagger in value despite the big run up in its own shares. Both have given back some of their gains and trade well below recent highs.

Yet investors remain convinced Callon will weather the latest storm as 97% of the CAPS All-Star members rating the oil and gas exploration play see it as outperforming the broad market averages. But you can tell us in the comments section below or on the Callon Petroleum CAPS page whether it's got the goods to grow again.

Generating interest
"Negawatts" is a buzz phrase that's been around for more than a decade, but it's only now gaining traction because the Federal Energy Regulatory Commission put in place rules that equate energy generation with demand reduction and calling for comparable compensation as a result. Taking demand off the overburdened electric grid is now worth getting paid for. In short, "negawatts" are the future.

The immediate beneficiaries will be demand-response aggregators such as EnerNOC and Comverge (Nasdaq: COMV), which assist consumers and businesses in remotely reducing their electrical consumption during peak demand periods.

CAPS member ScryingPool says that with EnerNOC testing new lows and a number of fundamental and technical factors favoring it, it's poised to generate new demand among investors.

Presently in its 52-week-low and oversold by weekly stochastic, market is dipped, good earnings forecast, good asset to debt ratios, small cap tech, power-solutions for grid redistribution is a scarce service and will be considered more seriously in the wake of Japan's recent disaster.

The Fool's free portfolio tracker can aggregate all the news about EnerNOC and the Smart Grid. Key tabs on whether this proves to ultimately be a dumb idea.

A smaller FormFactor
Considering there ought to be limited fallout from Japan's earthquake-tsunami-nuclear disaster on FormFactor's ability to churn out wafer probe cards, the current weakness is a buying opportunity for investors. There will be rolling blackouts across Japan to deal with the situation, which will have some effect, but FormFactor's stateside Livermore, Calif., facility can more than compensate for any disruption the Japanese facilities feel.

It's that ability to overcome the problem that has customers lining up for FormFactor's product. Elpida Memory, which took over from Intel (Nasdaq: INTC) as the card maker's biggest customer and accounts for more than 20% its revenues, apparently placed a large order, and others are putting in orders, too. Japanese rivals without other facilities to turn to are feeling the brunt of the switch.

While some CAPS members like oohaeagle see the potential for a sale of the company as a catalyst for share price growth, verylargelarry has been looking for FormFactor to return to profitability.

Its about to break through to profitability on the turnaround path. This will gap up then, followed by moves dependent on the recovery. Pretty firm buy here.

FormFactor remains a shell of its former high-flying self, but you can see if it can return to form by adding it to your watchlist.

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.

Intel is a Motley Fool Inside Value recommendation. EnerNOC is a Motley Fool Rule Breakers pick. FormFactor is a Motley Fool Hidden Gems pick. The Fool owns shares of and has bought calls on Intel. Motley Fool Options has recommended a bull call spread position on FormFactor. Motley Fool Options has recommended a diagonal call position on Intel. The Fool owns shares of EnerNOC, and FormFactor. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. 

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.