Wahhh wahh wahh I want it free and no strings attached and delivered to my door and everything to be done for me me me me me!
Of course it is free, there is no money changing hands, that is what 'free' means in this context. Free at the point of delivery. But there is a classical barter going on here. They do something for you, you in return do something for them. They aren't fucking touching you in special places, they are just encouraging you to translate some poxy sentences from one language to the other. You in return get to use your obviously immensely undervalued brain power to learn something useful. Try to whinge about it when they actually are trying to put one over on you, it makes you look like less of a twat.