When I first started out online some 6-7 years ago I first gravitated to Search Marketing on the free side - Organic traffic. I started out building websites and working on SEO.
Then I got into some alternative ways to drive traffic and sales like forum marketing (at the time our version of social marketing) and Joint Ventures.
And then... I discovered Google Adwords. I can't even tell you the profound effect it had on my business after I figured it out.. I say after I figured it out because the first go at it I failed miserably.
It wasn't until I discovered the right methods (and not just what Google taught me) that I started actually making money.
If you have been afraid to try Adwords or PPC in general, don't be. It seems complicated on the surface, but once you spend some time with it, it makes a lot of sense. It's not unlike placing ads in a newspaper. Difference here is you have a lot more control over who you're targeting, where you are targeting them and the price structure is different (per click).
If you are building niche websites, PPC can be a GREAT addition to your traffic sources. Especially if you are promoting products of your own, you have affiliate stores or reviewing other peoples' products in general. Once you learn Adwords/PPC you can quickly drive targeted traffic to your pages to see if you can make a profit.
If I launch a sales page of some kind, within an hour I can be testing a dozen ad groups to see if I can convert PPC traffic.
If I just wrote a review of an eBook, software or some other product, within an hour I can be testing a dozen ad groups to see if I can convert PPC traffic.
If I just set up an affiliate store page full of a particular kind of physical product or group of products, within an hour I can be testing a dozen ad groups to see if I can convert PPC traffic.
Once you learn it, it's very, very easy to set up and easy to "test" traffic to see if you got a winner.
If you need a good program to teach you how to do that, of course, you can check out my site here where I've been teaching people these methods for years: Campaign Blasts Method
I won't kid you.. there is a learning curve with PPC. But the good news is you have total control over your budget, your costs and if you follow a good method, you'll only target those that are interested in the products and services you promote - thus saving costs.
Give it a try! Or try it again.. if you failed the first time like I did. No quit! 
-Matt Levenhagen