Wondering how to build up your client base? These resources offer an affordable way to build networks — and tap into existing ones — to help your business get off the ground.

When I was in law school, I took a class on how to run your own law office, and the topic on everyone’s mind was, “Where in the heck will we get clients?” Even though I was interviewing for and wanted to get a job at a big firm (which I did), looking back, I can see now that I was plotting my escape from corporate America even then.

A few years later, it was time to put my plan into action. But the question was the same: Where would I get clients? I began to interview every successful solopreneur I knew, and essentially their answers boiled down to the following:

- networking

- advertising, and

- networking some more

And while that might seem like some pretty thin advice, the thing was, back then those really were the options. And somehow I made it.

The good news is that these days there’s no shortage of places to get viable leads, and most are both highly effective and quite affordable. You know the drill: Google ads, e-newsletters, Facebook ads and campaigns, tweets and blog specials, yada, yada, yada.

Is there anything new under the sun? I think there is. If I was to give a new entrepreneur advice today on where to get leads and find clients, I would point to three very viable — but a tad under-the-radar — options:

1. Craigslist. Sure, we all know, love and use Craigslist for getting rid of old stuff in the garage (or buying new old stuff for the garage), but you make a mistake if you discount what a great resource the site is for business opportunities.

First of all, the job listings are a virtual cornucopia of business leads. Yes, of course, jobs are listed, but so too are part-time gigs, contract positions, requests for proposals and the like. Beyond that, there’s also a listing called “Gigs,” and beyond that even, an area called “Services.” And what if you’re selling a product? Well, listing your products for sale in the right area will prompt even more leads and potential customers.

Best of all: It’s free.

2. Project-bidding sites. I would’ve really loved these sorts of sites if they were around when I was still practicing law — sites like Elance, oDesk, Guru, Freelancer.com, etc. These sites are amazing, listing tens of thousands of contract opportunities a day for the self-employed and other small-business people to bid on.

Let’s take Elance, for example (the company I happen to know best because I do some work with it). Elance is a fantastic all-in-one solution for both corporations and contractors. Corporate clients list projects through the Elance platform, and the contractors can then bid on those contracts and use the Elance virtual workplace and guaranteed pay system to complete the work. Pretty cool.

Bottom line: There are thousands of companies that not only need your help, but are actively seeking it out on these sorts of sites. It’s your job to get on these platforms, let them know you’re out there and get some of this available work.

(By the way, if you’re a solopreneur, let me also suggest that you check out my site, TheSelfEmployed, which is chock-full of useful information for the self-employed.)

3. LinkedIn. Sure, you have a LinkedIn account, and maybe you even have a couple hundred contacts. But do you use them? Have you ever really considered what an incredible resource and opportunity LinkedIn is?

Consider the San Francisco entrepreneur who gets most of his business through LinkedIn: He scours the site looking for potential partners and other people with whom he would like to do business, or else folks he would like to sell his services to. He then figures out if any of his contacts on LinkedIn know these people, and uses them to get personal introductions. He then meets those leads and closes the deal — or not. Either way, he sure does save time and money.

And that is the beauty of LinkedIn. What is the point of having all of these contacts if, like most people, you don’t use them? So use them.

How? Well, LinkedIn has a very powerful search feature that lets you search for people by name, industry, title, keyword, region, company and more. Do that, and not only will you get a list of viable leads, but you’ll also get a list of people you know who know those people. And since nothing beats a word-of-mouth introduction, a LinkedIn lead is often a very hot lead. And away you go.

So, happily, gone are the days when you had to either network (the old-fashioned way) or advertise your way to success. These days, there are a lot more options available (and better ones at that).

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