Actually, you DO NOT have a free plan. I tried it on my website. At first it seemed to work fine as I was well below the 2000 words limit. In a few days the plugin was not working as I have just surpassed the limit, although I have not added any content to my website. Then I deleted some of my content, but again in several hours I was again just above the limit. I excluded urls that included more than 700 words from translation, and guess what…? Again in a few hours I was just above the limit. It turned out that the plugin selects some lengthy paragraphs and translates them twice, making sure you are always just above the limit for the free version.