You don't need the investing acumen of Warren Buffett or the riches of a trust fund baby to achieve financial success.

Small sums of money invested monthly in undervalued small-cap stocks offer hope for your greatest returns. They offer the best growth opportunities for growth because they're mostly ignored by the big investors.

Below we screen for stocks under $3 billion in market cap, offering earnings surprises of 15% or more in the previous quarter, with long-term earnings growth forecast to be at least 15%. We'll then filter our findings through the collective investing wisdom of the 170,000 members in our Motley Fool CAPS community.

Here are some of the stocks this simple screen found:

Company

Market Cap

EPS Act. vs. Est.

Avg. Analyst 5-Yr EPS Est.

CAPS Rating (out of 5)

Fuel-Tech (Nasdaq: FTEK)

$214 million

$0.04 vs. $0.02

20%

****

Internap Network Services (Nasdaq: INAP)

$338 million

$0.02 vs. $0.01

19%

*****

Overstock.com (Nasdaq: OSTK)

$360 million

$0.63 vs. $0.43

20%

*

Sources: Yahoo! Finance, Motley Fool CAPS.

Of course, this is not a list of stocks to buy -- just a starting point for more research. We need to look more closely at these companies to see whether analysts' faith in them is well-founded.

An alternative opportunity
With cap-and-tax all but dead, nuclear power under assault, and alternative energy sources like solar and wind still trying to find a firm footing, natural resources that the U.S. has plenty of -- like natural gas and coal -- can once again be seriously considered to wean us off our dependence on foreign sources of fuel.

Coal-fired power plants have been seen as a dirty source of energy. That ought to give Fuel-Tech's pollution-control systems a better opportunity to gain ground, though rivals in the space like Foster-Wheeler (Nasdaq: FWLT) and Babcock & Wilcox will want to advance their own low nitrogen-oxide (NOx) burners.

The problem has been with the other plentiful resource, natural gas. Supplies have remained high, costs low, and after coal came under attack, many utilities began powering up natural gas plants. CAPS members remain bullish about Fuel-Tech's potential, however, thinking that not only will its low NOx burners find traction, but that its Fuel Chem business will see growth, too. It's been able to turn in a string of profitable quarters based on both operations.

Some 97% of the 1,019 CAPS member rating the pollution control specialist believe it will outperform the broad market averages. Cast your vote on its future on the Fuel-Tech CAPS page and see whether there's a future in clean coal.

A bend in the road
Although Akamai (Nasdaq: AKAM) handles about 20% of all Internet traffic, there's been no shortage of competition from Level 3 Communications and Internap Network Services. Yet despite a somewhat disappointing fourth quarter penny-per-share GAAP loss, Internap looks like it has turned the corner toward showing some consistency in reporting operating profits. It might not yet resemble Akamai or Rackspace (NYSE: RAX), but it's getting there.

The CAPS community is rallying behind the vendor of data-center and network services, boosting it from three to five stars in little more than a month's time, as CAPS member SnowBawl noted, but All-Star members are also out in force with only one thinking it won't beat the Street.

Add Internap to your watchlist to follow along and see if management really is making a change for the better, then head off to the Internap Network Services CAPS page and give us your thoughts on how it can convert those operating earnings into GAAP profits.

Man the ramparts
Like Amazon.com (Nasdaq: AMZN), online retailer Overstock.com faces mounting challenges from cash-strapped states looking to have the e-commerce sites collect sales taxes for them. Overstock has tended to follow Amazon's lead in shutting down affiliate sites in those states where the legislatures impose the taxes.

Of course, if that were Overstock's only problem, it might be able to garner more than a one-star rating from the CAPS community. But multiple restatements of its financials lends credence to its critics charges that it is living on borrowed time. While it's been able to beat analyst estimates, how long before it has to revise them again?

Highly rated CAPS All-Star TheMiracleDJR says you can't go wrong betting against Overstock, but benedekgb thinks its colorful CEO is one worth supporting. Let us know in the comments section below or on the Overstock.com CAPS page whether the Sith Lord still has the retailer in his sights or if it will be able to overcome past financial reworkings.

Foolish final thoughts
Stock investing is not brain surgery. Finding good, undervalued companies is not as difficult as the professionals want you to think. You just have to commit to starting now, and do so regularly. Now's the time to begin!

Akamai Technologies and Rackspace Hosting are Motley Fool Rule Breakers picks. Amazon.com is a Motley Fool Stock Advisor choice. 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 interest in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.