Everywhere you turn, businesses have closed up shop or they have been shut down due to the dismal nature of the economy over the last few years; but green enterprises are booming -- continuing to buck the downward trend. There is much to be learned by adopting the ideologies, both old and new, that eco businesses are setting forth - tips that can help your small business, whether you are an "eco" business or not. Here's a look at five green business types that are turning big profits in a down economy, and how you can cash in by following their sage business practices.

1. Bicycle shops: Build a business based on service

Bike shops exemplify the smart model of starting a business based on repair and service -- forging ongoing relationships with customers -- rather than one-time sales. Bicycle shops across the country have been reporting big business based on commuters' dwindling interest in expensive gasoline and sitting it traffic during a recession. Co-owner of a small but bustling bike shop in New Riverside, Garfield Cooper offers, "People can't afford to pimp their cars these days, but they can fix up their bikes." 

Owner of a vintage bike shop in San Francisco, Sasha Grigorovich-Barsky shares that, "[Bike] repair has definitely been beneficial to us because more people are likely to go into their back garage and find that bike that needs a little bit of work and go get it fixed rather than spending another $600.00 on a brand new bike." And Minnesota Business reports, "The spike in oil prices, which produced $4-a-gallon gas, led to a similar spike in bike sales and service. The number of bike commuters in our area doubled over the course of the year, and in the process they bought new bikes, refurbished old ones and accessorized, to the glee of shop owners metrowide."

2. Zipcar: Create community based on resource-sharing

Zipcar's motto is: "wheels when you want them." Instead of buying or renting a car, you can go green and share a car via a subscription with their car service, available in more than 50 cities across America, Canada and the UK. Zipcar reckons that "members report an average monthly savings of more than $500 compared to car ownership." 

CEO of Zipcar, Scott Griffith believes the company will grow 15-25 percent over the next few years. He adds, "Car-sharing is a successful business proposition, because it presents a cost-effective solution for urbanites who don't want the hassle, expense or eco-guilt of owning a vehicle."Additionally, the company reports that "Ninety percent of our members drove 5,500 miles or less per year, [which] adds up to more than 32 million gallons of crude oil left in the ground." Add these eco-benefits to the staggering statistic that "the car sharing market is expected to hit $3.3 billion by 2016," and Zipcar is speeding toward monumental success.

3. Thrift stores: Find treasure in someone else's trash

Eco-fashionistas have been touting the sensibility and style inherent in vintage clothing for years. If you're looking for green fashion and you're short on or want to save some literal green, hitting up thrift stores in search of savvy finds to wear is an excellent option, and you certainly won't be alone in doing so. According to an MSNBC report in 2008, "The Salvation Army and Goodwill Industries International, the nation's two largest charitable resale organizations, report[ed] year-to-date sales increases of 6 percent to 15 percent." And Adele Meyer, executive director of the National Association of Resale & Thrift Shops states, consumers "can't change the price of gas. They can't change the price of food. They can't make the stock market go up again, but they can control the price of clothes and furniture by being a savvy shopper."

4. Tailors and cobblers: Resuse and repair

Have you gone shopping in your closet lately? Chances are, there are some good finds lurking on your hangers! Even if some of your classic favorites need to be revamped, refitted, or resoled, that's what tailors and cobblers are for. And in this economy, where consumers are reviving what they have, as opposed to ringing up new items on a store register, shoe and clothing repair businesses are indeed fashion forward. For a glimpse into one small business owners success, Gerry H. Heiser, owner of Mr. Van's Shoe Repair offers, "Anytime during a recession, depression, service industries tend to do better... unfortunately, when things go bad for business, things go good for me. That seems to be the way it is." Last year, Heiser's business increased 50-75 percent due to repairs on shoes, purses and jackets.

5. Green construction: Build for long-term sustainability

Despite a flat construction/housing market in general, Green Building Elements declares, "the market for green homes is increasing, which is good news. In tough economic times, buyers are looking for efficiency and quality in their purchases." And Sustainable Business Oregon adds, "All this comes at a time when construction spending fell to a 10-year low of $805 billion in July, and investing in projects is down by 34 percent from the February 2006 peak, according to the Associated General Contractors trade group. Builders and construction-related businesses say green is in high demand because of its return on investment, but also because being environmentally responsible can boost a project’s profile and the developer’s reputation, providing a market edge over the competition." 

The bottom line: green isn't merely a fuzzy "feel-good" business practice to make you feel like a better person - it can also be a smart business strategy.