There might have been a box to uncheck if you didn't want the free sub.
Oh, I just checked an example of one of their contests - there's a separate link for entering if you don't want the free subscription
- the one I used as an example is US only, I couldn't find a CDN one - so check back on the entry page you used to see if it is similar
http://www.womansday.com/sweepstakes/27567
Don't worry - they give these instructions -
If you like what you see, you'll get 11 more issues (12 in all) for just $7.99 —
that's 76% less than others pay on the newsstand. If not, return the bill marked "cancel" and keep the first issue with no obligation. You'll still be eligible to win the sweepstakes.