gTranslate
Weglot is also "Free" but well, if you need to get a good use of them, you'll need to open your pockets.gTranslate is free ... but it looks ugly with the original plugin themes unless you do a bit of CSS editing. You also need to insert a shortcode into a theme file, like footer.php or b-social.php. I tried it ... but then decided to scrap it. Customers can use Google Translate in their browsers if they need to. The normal Google Translate Plugin is OK ... but again, you need to insert a shortcode somewhere.
I am not looking a way to play and waste time...