Recently, we had some very cold and windy weather, which led me to discover that the draft near our front door is worse than I thought. I used to just shove a towel near the door in cold weather. There are draft blockers that you can purchase, but I'd rather make one myself to save money. I saw a blog that made one from an old pair of tights. Just cut off one leg, stuff it, and tie off the end. Quick, easy, and free, and no more drafts.
There's really no need to buy a draft blocker, any piece of cloth which can fill the gap will do. You could even just position some furniture near the door to help dispel some of the cold breeze.