It appears that the free sample papers available at the site have been written by their existing pool of writers. That means, the student can pick a sample paper, read through it as if considering hiring the writer, and base his hiring choice on the way the sample paper was written. This is something that I would advise students to consider very well since it will show him/her if the writer meets his criteria in terms of writing skill, knowledge of the topic, and other considerations. The writer has the option to hire the writer whose sample work he reviewed or, if he wants to use the sample paper to develop his own paper. I see nothing wrong with either choice. The student is given the opportunity to make an educated decision in this case, which I hope he decides to take. Use the service you feel is best for you, based on the actual writer skills that will be offered to you through the sample essay.
The opinions are that of the author's alone based on an individual capacity. Opinions are provided "as is" and are not error-free.