With these deals for cheap or free subcriptions, ALWAYS cancel before the renewal. That's where they will more than make up for the original price.
Usually if you can find the fine print, it will tell you how much you'll get robbed for.
It's like those deals for half a dozen Dr. Seuss books for $1.99 or whatever they charge now...they'll start shipping single books to you for $25 every month if you don't cancel right after you get your cheap books.