At one time PLR articles had to be bought through sites with a membership fee, but nowadays there are several websites that sell them in small packages. This gives website owners the chance to look over the PLR articles and make certain they are articles that are of high quality before they purchase more PLR articles from the same site.
PLR content can be used in several ways by website owners. A few PLR articles can be combined into fewer, longer articles for a new spin on the articles themselves. They can also be put together into a report or ebook that can then be sold on the website owner's site. They can also be reworded or rewritten to create something entirely unique for your site.
There have been a few people out there who see their PLR articles as a quick way to bring in money, even if they don't really have the skills needed to write those articles. Beware of those PLR sellers who are not really writers and don't have the skills to create unique content needed for their PLR article packages. When choosing your PLR articles, find an experienced writer who knows how to create web content articles and has experience in writing PLR articles.
Read the way the website itself is worded. This will be a clue to what the PLR article packages themselves will be like once you buy them. Are there any typos in the website's copy? Is the language hard to understand? Does it sound like the PLR writer is a professional writer? If not, it might be time to look elsewhere. If you do find a website that's written well and that flows well, consider trying out a few PLR articles. They are one of the cheapest ways to get high quality web content articles.