Penny stocks are one way to double your money, though it's fraught with risk, but there are equally shiny opportunities trading at the other end of the price spectrum, too. I call 'em "three-digit stocks," yet if they're anything like Berkshire Hathaway, they can trade in the four-, five-, and six-digit range, too.

penny stock might not be a good buy simply because it's cheap, and a three-digit stock shouldn't scare you away just because it carries a hefty price tag. Handsome is as handsome does. Let's check in with the Motley Fool CAPS community to see which of the high-priced stocks below earn the greatest confidence from our investor-intelligence database:

Stock

CAPS Rating (out of 5)

3-Digit Price

Return on Capital, TTM

BlackRock (NYSE: BLK)

***

$168.62

7.5%

Mitsui (Nasdaq: MITSY)

*****

$320.00

2%

Oil Services HOLDRS (NYSE: OIH)

****

$120.53

NA

Sources: Capital IQ, a division of Standard & Poor's, and Motley Fool CAPS.

But just because these stocks are purring is no reason to jump into them blindly. Catching a tiger by the tail -- or a knife falling from on high -- can end up leaving you scratched and bleeding. That's why we recommend you use this list as a launchpad for your own research and analysis.

Highfalutin' honeys
While oil prices have eased as the dollar gained a little strength, the overall trend is up since quantitative easing is expected to weaken the greenback further. But rather than trying to pick and choose which oil-service companies might benefit -- after all they are the picks and shovels of the oil industry -- investors might simply opt for the oil services HOLDRs, a basket of niche companies.

Structured as a trust, HOLDRs are similar to ETFs by allowing investors to buy just a portion of specific sectors, but they differ in that they purchase the common stock of the individual companies rather than the industry index.

The risk with the Oil Services HOLDRs is the holdings are very concentrated, with only 14 stocks in the basket. More than half of its assets in just four stocks, and 30% of its assets are placed in Transocean (NYSE: RIG) and Schlumberger. OIH, though, stands a good chance of becoming even more concentrated, as it is a static, unmanaged trust, as opposed to an ETF, which can expand its holdings depending upon its underlying index.

With 93% of the nearly 500 CAPS members rating the HOLDRs to outperform the broad market averages, the feeling is that demand for oil services will continue to be in high demand. Is the oil services HOLDRs right for you? Add it to your My Watchlist page and have all the Foolish news and analysis compiled for you in a single place for review.

Not so rough
As popular as oil is with traders, copper is also gaining a patina of respectability again. If the economy is ever going to rebound, it's going to be taking copper along for the ride because of its many industrial uses, but equally important the mining of the metal produces a number of additional, equally valuable commodities. Sure, gold and copper are often found together -- that's one of the theses for investing in Freeport-McMoRan Gold & Copper (NYSE: FCX) -- but so is molybdenum, and the higher prices realized for both enabled Taseko Mines (NYSE: TGB) to report higher earnings this past quarter.

Tellurium is another byproduct from bringing copper to the surface, and is a key component in First Solar's (Nasdaq: FSLR) solar panels, as is rhenium, which used in the production of high-temp turbine engine components.

All of this helps explain why there is copper rush among ETF backers. BlackRock, in its off-again-on-again saga, has filed with the Securities and Exchange Commission the paperwork necessary to become an ETF that physically holds copper stores. Going by the name iShares Copper Trust, the ETF will create baskets that hold 2,500 shares of 25 metric tons of copper.

It's that sort of shrewd management that has highly rated CAPS All-Star member Jeffreyw seeing the investment management firm as being top-notch: "Great management team and proven results in every economic environment."

You can mine the opinions of other CAPS members on the BlackRock CAPS page and add your own views on whether it can capture the new gold rush.

Triple-digit titans
Japan's trading house Mitsui might benefit as well from rising copper prices and interest. Earlier this year, it took a 25% stake in a Chilean copper mining project owned by Pan Pacific Copper, but it also has stakes in a broad range of industries, from coal to oil. In fact, Mitusi might have some liability for the Gulf of Mexico oil spill, as one of its subsidiaries owned a 10% stake in Transocean's Deepwater Horizon rig.

While the Japanese conglomerate flies under the radar of most of the market, 97% of the CAPS members rating Mitsui believe it will turn in market-beating results. You can put Mitsui into Fool.com's free portfolio tracker, My Watchlist, and add your opinion on the Mitsui CAPS page, too.

Count to 10
These three-digit stocks might be on their way to even higher valuations. That's why it pays to start your own research in 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.