To take advantage, you must book by 11:59pm on January 2. Additionally, the code is only good for flights on these specific dates: January 9, 10, 13, 17, 18, 20, 23, 24, 25, 30, 31, February 3, 6, and 7.
The deal is impressive, if short-lived. However, be sure to get a full picture of how much you're going to spend on the trip before buying tickets. Frontier charges for seat selection. Though, you can have your seat assigned to you at the airport for free. The airline also charges for any luggage beyond a personal item.
To boot, Frontier's on-time arrival rate is nothing to write home about. (Unless you're writing about your frustration because your flight was delayed.)
Nonetheless, it's a cheap flight, and if you're capable of packing like a hero, you're probably going to be able to make this work and get out of town for ridiculously cheap.