EDIT: I'm bumping this post from Jan. 2 because it's still available for the next week!
Now these kind of freebies are the ones that sucked me into this world a decade ago! The fact that we have two different ways to win a free Snickers candy bar is merely icing on the cake. Scratch that, imagine icing on a Snickers!
Visit their Facebook page and enter the contest. Even though it's called a contest, it seems like everybody is winning. You should see the image above with a confirmation message below saying you'll receive the prize in 6-8 weeks. Hopefully winter storm Hercules stays around long enough to make sure they don't melt.
If you're not a fan of Facebook, then text SNICKERS to 78787. They'll reply with a confirmation PIN, which you then.
I will add that I texted them an hour ago and haven't heard back, so I'm not sure how long this step takes.