For those who are good article writers, they can certainly get by and make their lives a lot easier by writing articles for companies wishing to promote their products and/or services. But one must be very careful how one does this because a writer could get them selves in legal hot water if they use deceptive techniques to promote the companies they are trading or bartering with.
To further clarify my comments about being careful about bartering. There are ways to disclose that you have a relationship with the company. I wrote this article on the subject;
The best way to disclose your bartering in article writing, would be to disclose in your Byline; Professional Writer or Public Relations or "likes to write about the companies she does business with" or such. Or somewhere in the article describe that you simply loved the sample that the company had provided for the article and "I am keeping it too" or something of this nature. Or, you might disclose the company gave me some coupons, I went there and feel in love with the service and products.
You can either work this into the article or allow it to be understood in your byline that you are in the business of public relations some how. Since many online article submission websites or at least the best ones allow for multiple bylines, the write would be advised to create a new one carefully worded for you bartering and then the sky is the limit.
Just stay away from "BUZZ Marketing" tactics as the FTC considers them to be deceptive and in a way they really are. The person who reads the article has the right to know of your motives. Indeed you will see many of the Home Improvement TV Shows will use products donated for the show and they always disclose it. You can do the same thing without taking away from the article and you really should be thinking here. Stay above board, as it is the best for all concerned. There is a write way and a wrong way. Consider this in 2006.