Most of the services depend on creating a writer account and then submitting it to the article directories, you might as well do this yourself to get a feel for the process, so when you do outsource it you know exactly what needs to be done by the service, you can start by submitting articles to Ezinearticles, it is respected by the search engines, for the number one reason that they scrutinize each article manually for spelling, grammar and punctuation, and also the relevancy of the title, description, and content that they match
free articles publishing as it is would be of no use. Avoid duplication. You will have to rewrite it again or spin it and make look original.