Monday, December 17th is Free Shipping Day! That is the last day you can order online with guaranteed delivery by Christmas Eve.
On that day, over 1000 online merchants will ship your order for free, with no minimum order (as far as I know, I have not tried all the retailers so I can’t say that for sure). If you want to order from a few different places this could save you quite a bit of money.
Some of my favorite merchants (ones that I have actually purchased from, but not all of them online) participating are: