Flight to Nicaragua for free

I know how this may sound, but I really heard from a friend that it is possible to fly to Nicaragua for free. Now, she is not sure if it is because of the free flights, or there is something else that makes it possible, so I would really like to hear if there is anyone who knows more about this. It sounds almost incredible to me…

To be honest with you this is the first time I hear about anything like that. I know it is possible to win a free ticket, but to fly for free just like that…I have to admit that I doubt something like that is possible. I mean, who would do such a thing? And why would any airline company do that?