It's super easy to win; just comment on their posts until one day they pick you, then follow the instructions. Some say they're fake, but I've won two products and gotten them both so maybe they're just sore because they haven't won yet. It's legit, it's free, and it's exiting to get picked!
Tip for consumers: Winners are randomly selected, so don't feel like you're doing it wrong or that they're a scam. There are a lot of people trying to get the freebies, so with all the competition it can take a while sometimes. Hang in there!