Not sure about free but you can check WordAI, SpinRewriter, The Best Spinner, Spinner Chief etc. to name a few. In case of rewriter, none of them are perfect and you need to proofread yourself. And normally the price is also dependent on the quality. WordAI is regarded as the best and is the most expensive. Next comes SpinRewriter and Spinner Chief (both of which I own/use) and both work ok.. then comes TBS where a lot of manual reading is needed.. and so on. Free is not always the best. Probably you would take less time in manually writing the article instead of a free spinner in case you need only one copy.