Want to keep the planet and your portfolio green? The Fool shows you how in our special series on Earth-friendly investing.

It's not easy being green, but there are still plenty of companies hoping to cash in on consumers' growing interest in environmentally responsible lifestyles.

This can definitely be a good thing. Toyota (NYSE: TM) took the car market by storm with its iconic Prius hybrid, and carmakers like Ford (NYSE: F) have bowed to ensuing demand and beefed up their hybrid offerings. Whole Foods (Nasdaq: WFMI) is using solar energy to generate part of the power for a handful of its stores. Heck, even Wal-Mart (NYSE: WMT) claims that it is able to save enough energy to power almost 150,000 homes per year simply by using skylights and light sensors in its stores.

But there's a flip side to all of this. As green living gains momentum, more companies are seeing dollar signs, and more green products are coming to the market. I wouldn't be surprised if another year or two finds us overwhelmed with marketers pushing green products on consumers from every direction, guilting us into spending more to save Mother Earth. We may risk ending up with mass "green fatigue," never wanting to hear the word "green" again.

Shoppers are already growing skeptical. An article in the Las Vegas Review Journal noted that while more people are concerned about the environment, consumers are increasingly dubious about many products' eco-friendly claims. The article specifically mentioned very mixed reactions to the new green line from Clorox (NYSE: CLX).

Fortunately, there are very simple ways for consumers to stay green without having to pony up for special green products. Good ol' vinegar can be used as an all-purpose cleaning agent, and if you want to get a fresh scent going, a lemon can do the trick. Buying the fluorescent light bulbs that GE (NYSE: GE) or others make can be great, but simply turning off lights that you're not using can go a long way, too. And while I think hybrid cars are a big step forward, finding ways to drive less can save even more gas and pollution.

That may all seem more than just a bit boring. But just like in investing, doing the little things right over and over again, rather than jumping at every passing trend, tends to produce some pretty remarkable results.

Wal-Mart Stores is a Motley Fool Inside Value recommendation, and Whole Foods Market is a Motley Fool Stock Advisor pick. Try any of our Foolish newsletters today, free for 30 days.

Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. The Fool's disclosure policy, having misunderstood the true meaning of "green," needs some tips on how to get the lime-green dye out of its hair.