After months and months of trying to sell things, I have found there is no magic bullet or one free advertising system that will make you a fortune. Actually, you need to get several, invest time in the slower platforms to bring yourself nearer the top for search results, and interlink them.

Here are the platforms I use, in order of dollar-and-cents effectiveness:

1. Craigslist. If you have something tangible you need to get out into the world in exchange for a few dollars, Craigslist has been a godsend for my friend Ed, who sells vintage clothing. It's gotten me 10% of his sales too as a finder's fee, the easiest $50 I've ever made. After painstakingly posting dozens of listings on eBay competing with sellers who let $200 dresses go for 50 cents, the results were much more immediate and rewarding, and infinitely more affordable (free!). It's also gotten me several good job offers.

If you're a buyer or looking for a job or service on CL, however, you can get easily taken. I've wound up locked in a condo for two weeks with a CL nutjob and my car is sitting disabled at my last CL employer's business as I write this.

With the potential buyer's mindset and previous experiences in mind, if you do plan to sell through Craigslist, offer proof you're not a fly-by-nighter who will vanish at the first sign of payment. Mention your website, credentials, testimonials, anything you can that will show you're a true businessperson, and not someone out to hurt and disappoint people until you have to vanish. If your potential customers haven't dealt with someone scummy on CL, it's very likely they've seen some shady offers on there, so be sure to stand out as a top-notch seller from your title to your closing sentence.

2. Facebook. FB has to keep the spam down to make it a reasonably enjoyable place to be (no, I won't join your Mob Wars mob), but compared to Web 1.0 companies that were so foamy-mouthed about posting links on their sites, it's a godsend. As long as you don't blatanty spam your business or product (try making fan pages, groups, videos, and other softer sells), you get to keep your account. I was even able to add eBay and posted link applications that let me get my auction listings out the minute they came out.

And not only have I gotten a lot of quality people as FB friends, I've met a lot of high school friends and obtained valuable marketing information for free. Favor forming alliances over selling appliances and you'll do well. Sell through viral ripples and not in a straight line.

3. MySpace. For the sheer number of friends one can have, MySpace still has the edge if you can attract people with your store-linked MySpace blogs and bulletins. However, MySpace is not as link-friendly as Facebook, and you will often have to weed through a ton of spambots, bands and other sellers to reach a target audience. Fortunately, MySpace is starting to ape Facebook's viral features so that there is a larger and wider ripple effect when you update your status, change your profile, et cetera. Getting a local support base is still much easier than FB (it's taken acts of Congress to join a Portsmouth, NH network over Portsmouth, England), and there's not a ton of app spam you have to filter through either. Think of it as social networking's PC, turned for the short term into a Mac.

4. Twitter. I love the application! There is so much important information amd there are so many business links that can be conveyed in just 140 characters, especially with the link-shortening power of TinyURL. Joel Comm has a fantastic resource on Twitterology and it's helped me maximize the give-and-take that makes the process so fun. With 25 followers, things aren't quite that effective yet, but I've gotten some good leads and this is how I heard about HubPages... from a few lines that Darren Rowse posted from his ProBlogger Twitter account.

5. Blogger. I admit, I'm not the world's most prolific blogger, so I've had mixed results with blogging. But if you are a person who is dedicated to getting your message out daily or weekly, and you're the kind of person who could wake out of a deep sleep and post all the benefits of your latest product or service, give Blogger a try. Don't go for straight spammery, though, saying "buy my product" and nothing more, unless you know how to make one heck of a sharp-looking business page. Humanize your presentation. Have fun. Link to blogs with similar goals, or go out on a limb and find one that is just plain entertaining. Check out http://problogger.net to get the basics down a piece at a time.

And for the love of all that is holy, monetize your blog with something besides pure AdSense until you hit it big. If you need something to pay the bills while your product takes hold and traffic grows, make partnerships with other advertisers directly. Pure AdSense is fine for a mid-sized or matured blog, but don't give away huge partner sales for just pennies when you're starting out. One or two Google ad units can still help you get the jump on that first sweet $100 down the road, but make sure you know your options before you prop up your free blog with advertising.

6. Plurk. To me, Plurk is like a weird, crazy uncle. You love him as you're growing up even though no one else understands him and he lives in his own little bizarre neighborhood. It's like a horizontal Twitter. The timeline feature is clunky but I like the novelty a lot, and you are granted special "Karma"-powered privileges the more you post quality Twitter-style pieces of information. I suppose there are top-secret algorithms that give you more Karma gravy, but it's been nice to see the small Karma bumps that have come from single posts. Again, you need to keep the original content high before you can convincingly promote your brazen affiliate or other commerce links, so this is one of the slower free advertising services you can sign up for.

7. Ryze and LinkedIn. I've only gotten a few tepid welcoming messages from both companies. I got a Ryze account with one of my second-string accounts. I've been getting weekly traffic updates free but there haven't been many responses from other marketers. LinkedIn, at least, recently sent me a guide explaining what to do with my account; Ryze, while respecting the Swiss-cheese sanctity of my inbox, hasn't given me any incentives to delve further into its system. These are solid companies, and they've carved out a niche for themselves, but I don't recommend them for people who want instantly powerful advertising, especially if you don't have a degree or two to decorate the refrigerator page of your profile with.

So, that is what has worked for me, in varying degrees of effectiveness. I hope at least a few of them help!