BuyDig offers the Garmin Vivofit Fitness Band with Heart Rate Monitor in Red, model no. 010-01225-38, for $47.99 with free shipping. That's the lowest total price we could find by $2, although most retailers charge $57 or more. (We saw it for $3 less two weeks ago.) It features personalized daily goals, progress tracking, and workout reminders.
It is not expected to arrive by Christmas.