It's hard to say as you don't usually see them on sale. I do know that Best Buy is selling one Surface Pro 3 model (as I remember) for $50 off on their black Friday sale
If you have the Discover IT credit card will refund price change differences up to 90 days from your purchase date so you can get it sooner too. I do a lot of my black friday shopping as soon as the ads hit and can avoid the lines and crowds with this trick